Update package.json

When the Serial software FIFOs overeflowed, the IRQ handler would not
read any more data from the hardware FIFOs.  This would cause the
IRQ handler to be continually called as soon as it exited since the
HW FIFOS were not empty.

Now always read every available HW FIFO entry and throw out any that
don't fit in the SW FIFO.

Also fix a too long by half stop bit timing in the PIOSerial receiver.

README.md

@@ -13,6 +13,7 @@ See https://arduino-pico.readthedocs.io/en/latest/ along with the examples for m
 * Raspberry Pi Pico
 * Adafruit Feather RP2040
 * Adafruit ItsyBitsy RP2040
+* Adafruit KB2040
 * Adafruit Macropad RP2040
 * Adafruit QTPy RP2040
 * Adafruit STEMMA Friend RP2040
@@ -145,6 +146,7 @@ The RP2040 PIO state machines (SMs) are used to generate jitter-free:
 * Servos
 * Tones
 * I2S Output
+* Software UARTs (Serial ports)
 
 # Tutorials from Across the Web
 Here are some links to coverage and additional tutorials for using `arduino-pico`

boards.txt

@@ -3313,6 +3313,493 @@ adafruit_macropad2040picodebug.menu.dbglvl.NDEBUG.build.debug_level=-DNDEBUG
 adafruit_macropad2040picodebug.menu.usbstack.nousb=No USB
 adafruit_macropad2040picodebug.menu.usbstack.nousb.build.usbstack_flags="-DNO_USB -DDISABLE_USB_SERIAL -I{runtime.platform.path}/tools/libpico"
 
+# -----------------------------------
+# Adafruit KB2040
+# -----------------------------------
+adafruit_kb2040.name=Adafruit KB2040
+adafruit_kb2040.vid.0=0x239a
+adafruit_kb2040.pid.0=0x8105
+adafruit_kb2040.build.usbpid=-DSERIALUSB_PID=0x8105
+adafruit_kb2040.build.usbpwr=-DUSBD_MAX_POWER_MA=250
+adafruit_kb2040.build.board=ADAFRUIT_KB2040_RP2040
+adafruit_kb2040.build.mcu=cortex-m0plus
+adafruit_kb2040.build.variant=adafruit_kb2040
+adafruit_kb2040.upload.tool=uf2conv
+adafruit_kb2040.upload.maximum_size=8388608
+adafruit_kb2040.upload.maximum_data_size=262144
+adafruit_kb2040.upload.wait_for_upload_port=true
+adafruit_kb2040.upload.erase_cmd=
+adafruit_kb2040.serial.disableDTR=false
+adafruit_kb2040.serial.disableRTS=false
+adafruit_kb2040.build.f_cpu=125000000
+adafruit_kb2040.build.led=
+adafruit_kb2040.build.core=rp2040
+adafruit_kb2040.build.ldscript=memmap_default.ld
+adafruit_kb2040.build.ram_length=256k
+adafruit_kb2040.build.boot2=boot2_w25q080_2_padded_checksum
+adafruit_kb2040.build.vid=0x239a
+adafruit_kb2040.build.pid=0x8105
+adafruit_kb2040.build.usb_manufacturer="Adafruit"
+adafruit_kb2040.build.usb_product="KB2040"
+adafruit_kb2040.menu.flash.8388608_0=8MB (no FS)
+adafruit_kb2040.menu.flash.8388608_0.upload.maximum_size=8384512
+adafruit_kb2040.menu.flash.8388608_0.build.flash_length=8384512
+adafruit_kb2040.menu.flash.8388608_0.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_0.build.fs_start=276819968
+adafruit_kb2040.menu.flash.8388608_0.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_65536=8MB (Sketch: 8128KB, FS: 64KB)
+adafruit_kb2040.menu.flash.8388608_65536.upload.maximum_size=8318976
+adafruit_kb2040.menu.flash.8388608_65536.build.flash_length=8318976
+adafruit_kb2040.menu.flash.8388608_65536.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_65536.build.fs_start=276754432
+adafruit_kb2040.menu.flash.8388608_65536.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_131072=8MB (Sketch: 8064KB, FS: 128KB)
+adafruit_kb2040.menu.flash.8388608_131072.upload.maximum_size=8253440
+adafruit_kb2040.menu.flash.8388608_131072.build.flash_length=8253440
+adafruit_kb2040.menu.flash.8388608_131072.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_131072.build.fs_start=276688896
+adafruit_kb2040.menu.flash.8388608_131072.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_262144=8MB (Sketch: 7936KB, FS: 256KB)
+adafruit_kb2040.menu.flash.8388608_262144.upload.maximum_size=8122368
+adafruit_kb2040.menu.flash.8388608_262144.build.flash_length=8122368
+adafruit_kb2040.menu.flash.8388608_262144.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_262144.build.fs_start=276557824
+adafruit_kb2040.menu.flash.8388608_262144.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_524288=8MB (Sketch: 7680KB, FS: 512KB)
+adafruit_kb2040.menu.flash.8388608_524288.upload.maximum_size=7860224
+adafruit_kb2040.menu.flash.8388608_524288.build.flash_length=7860224
+adafruit_kb2040.menu.flash.8388608_524288.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_524288.build.fs_start=276295680
+adafruit_kb2040.menu.flash.8388608_524288.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_1048576=8MB (Sketch: 7MB, FS: 1MB)
+adafruit_kb2040.menu.flash.8388608_1048576.upload.maximum_size=7335936
+adafruit_kb2040.menu.flash.8388608_1048576.build.flash_length=7335936
+adafruit_kb2040.menu.flash.8388608_1048576.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_1048576.build.fs_start=275771392
+adafruit_kb2040.menu.flash.8388608_1048576.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_2097152=8MB (Sketch: 6MB, FS: 2MB)
+adafruit_kb2040.menu.flash.8388608_2097152.upload.maximum_size=6287360
+adafruit_kb2040.menu.flash.8388608_2097152.build.flash_length=6287360
+adafruit_kb2040.menu.flash.8388608_2097152.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_2097152.build.fs_start=274722816
+adafruit_kb2040.menu.flash.8388608_2097152.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_3145728=8MB (Sketch: 5MB, FS: 3MB)
+adafruit_kb2040.menu.flash.8388608_3145728.upload.maximum_size=5238784
+adafruit_kb2040.menu.flash.8388608_3145728.build.flash_length=5238784
+adafruit_kb2040.menu.flash.8388608_3145728.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_3145728.build.fs_start=273674240
+adafruit_kb2040.menu.flash.8388608_3145728.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_4194304=8MB (Sketch: 4MB, FS: 4MB)
+adafruit_kb2040.menu.flash.8388608_4194304.upload.maximum_size=4190208
+adafruit_kb2040.menu.flash.8388608_4194304.build.flash_length=4190208
+adafruit_kb2040.menu.flash.8388608_4194304.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_4194304.build.fs_start=272625664
+adafruit_kb2040.menu.flash.8388608_4194304.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_5242880=8MB (Sketch: 3MB, FS: 5MB)
+adafruit_kb2040.menu.flash.8388608_5242880.upload.maximum_size=3141632
+adafruit_kb2040.menu.flash.8388608_5242880.build.flash_length=3141632
+adafruit_kb2040.menu.flash.8388608_5242880.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_5242880.build.fs_start=271577088
+adafruit_kb2040.menu.flash.8388608_5242880.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_6291456=8MB (Sketch: 2MB, FS: 6MB)
+adafruit_kb2040.menu.flash.8388608_6291456.upload.maximum_size=2093056
+adafruit_kb2040.menu.flash.8388608_6291456.build.flash_length=2093056
+adafruit_kb2040.menu.flash.8388608_6291456.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_6291456.build.fs_start=270528512
+adafruit_kb2040.menu.flash.8388608_6291456.build.fs_end=276819968
+adafruit_kb2040.menu.flash.8388608_7340032=8MB (Sketch: 1MB, FS: 7MB)
+adafruit_kb2040.menu.flash.8388608_7340032.upload.maximum_size=1044480
+adafruit_kb2040.menu.flash.8388608_7340032.build.flash_length=1044480
+adafruit_kb2040.menu.flash.8388608_7340032.build.eeprom_start=276819968
+adafruit_kb2040.menu.flash.8388608_7340032.build.fs_start=269479936
+adafruit_kb2040.menu.flash.8388608_7340032.build.fs_end=276819968
+adafruit_kb2040.menu.freq.125=125 MHz
+adafruit_kb2040.menu.freq.125.build.f_cpu=125000000L
+adafruit_kb2040.menu.freq.50=50 MHz
+adafruit_kb2040.menu.freq.50.build.f_cpu=50000000L
+adafruit_kb2040.menu.freq.100=100 MHz
+adafruit_kb2040.menu.freq.100.build.f_cpu=100000000L
+adafruit_kb2040.menu.freq.133=133 MHz
+adafruit_kb2040.menu.freq.133.build.f_cpu=133000000L
+adafruit_kb2040.menu.freq.150=150 MHz (Overclock)
+adafruit_kb2040.menu.freq.150.build.f_cpu=150000000L
+adafruit_kb2040.menu.freq.175=175 MHz (Overclock)
+adafruit_kb2040.menu.freq.175.build.f_cpu=175000000L
+adafruit_kb2040.menu.freq.200=200 MHz (Overclock)
+adafruit_kb2040.menu.freq.200.build.f_cpu=200000000L
+adafruit_kb2040.menu.freq.225=225 MHz (Overclock)
+adafruit_kb2040.menu.freq.225.build.f_cpu=225000000L
+adafruit_kb2040.menu.freq.250=250 MHz (Overclock)
+adafruit_kb2040.menu.freq.250.build.f_cpu=250000000L
+adafruit_kb2040.menu.freq.275=275 MHz (Overclock)
+adafruit_kb2040.menu.freq.275.build.f_cpu=275000000L
+adafruit_kb2040.menu.freq.300=300 MHz (Overclock)
+adafruit_kb2040.menu.freq.300.build.f_cpu=300000000L
+adafruit_kb2040.menu.opt.Small=Small (-Os) (standard)
+adafruit_kb2040.menu.opt.Small.build.flags.optimize=-Os
+adafruit_kb2040.menu.opt.Optimize=Optimize (-O)
+adafruit_kb2040.menu.opt.Optimize.build.flags.optimize=-O
+adafruit_kb2040.menu.opt.Optimize2=Optimize More (-O2)
+adafruit_kb2040.menu.opt.Optimize2.build.flags.optimize=-O2
+adafruit_kb2040.menu.opt.Optimize3=Optimize Even More (-O3)
+adafruit_kb2040.menu.opt.Optimize3.build.flags.optimize=-O3
+adafruit_kb2040.menu.opt.Fast=Fast (-Ofast) (maybe slower)
+adafruit_kb2040.menu.opt.Fast.build.flags.optimize=-Ofast
+adafruit_kb2040.menu.opt.Debug=Debug (-Og)
+adafruit_kb2040.menu.opt.Debug.build.flags.optimize=-Og
+adafruit_kb2040.menu.rtti.Disabled=Disabled
+adafruit_kb2040.menu.rtti.Disabled.build.flags.rtti=-fno-rtti
+adafruit_kb2040.menu.rtti.Enabled=Enabled
+adafruit_kb2040.menu.rtti.Enabled.build.flags.rtti=
+adafruit_kb2040.menu.dbgport.Disabled=Disabled
+adafruit_kb2040.menu.dbgport.Disabled.build.debug_port=
+adafruit_kb2040.menu.dbgport.Serial=Serial
+adafruit_kb2040.menu.dbgport.Serial.build.debug_port=-DDEBUG_RP2040_PORT=Serial
+adafruit_kb2040.menu.dbgport.Serial1=Serial1
+adafruit_kb2040.menu.dbgport.Serial1.build.debug_port=-DDEBUG_RP2040_PORT=Serial1
+adafruit_kb2040.menu.dbgport.Serial2=Serial2
+adafruit_kb2040.menu.dbgport.Serial2.build.debug_port=-DDEBUG_RP2040_PORT=Serial2
+adafruit_kb2040.menu.dbglvl.None=None
+adafruit_kb2040.menu.dbglvl.None.build.debug_level=
+adafruit_kb2040.menu.dbglvl.Core=Core
+adafruit_kb2040.menu.dbglvl.Core.build.debug_level=-DDEBUG_RP2040_CORE
+adafruit_kb2040.menu.dbglvl.SPI=SPI
+adafruit_kb2040.menu.dbglvl.SPI.build.debug_level=-DDEBUG_RP2040_SPI
+adafruit_kb2040.menu.dbglvl.Wire=Wire
+adafruit_kb2040.menu.dbglvl.Wire.build.debug_level=-DDEBUG_RP2040_WIRE
+adafruit_kb2040.menu.dbglvl.All=All
+adafruit_kb2040.menu.dbglvl.All.build.debug_level=-DDEBUG_RP2040_WIRE -DDEBUG_RP2040_SPI -DDEBUG_RP2040_CORE
+adafruit_kb2040.menu.dbglvl.NDEBUG=NDEBUG
+adafruit_kb2040.menu.dbglvl.NDEBUG.build.debug_level=-DNDEBUG
+adafruit_kb2040.menu.usbstack.picosdk=Pico SDK
+adafruit_kb2040.menu.usbstack.picosdk.build.usbstack_flags="-I{runtime.platform.path}/tools/libpico"
+adafruit_kb2040.menu.usbstack.tinyusb=Adafruit TinyUSB
+adafruit_kb2040.menu.usbstack.tinyusb.build.usbstack_flags=-DUSE_TINYUSB "-I{runtime.platform.path}/libraries/Adafruit_TinyUSB_Arduino/src/arduino"
+
+# -----------------------------------
+# Adafruit KB2040 (Picoprobe)
+# -----------------------------------
+adafruit_kb2040picoprobe.name=Adafruit KB2040 (Picoprobe)
+adafruit_kb2040picoprobe.vid.0=0x239a
+adafruit_kb2040picoprobe.pid.0=0x0004
+adafruit_kb2040picoprobe.build.usbpid=-DSERIALUSB_PID=0x8105
+adafruit_kb2040picoprobe.build.usbpwr=-DUSBD_MAX_POWER_MA=250
+adafruit_kb2040picoprobe.build.board=ADAFRUIT_KB2040_RP2040
+adafruit_kb2040picoprobe.build.mcu=cortex-m0plus
+adafruit_kb2040picoprobe.build.variant=adafruit_kb2040
+adafruit_kb2040picoprobe.upload.tool=picoprobe
+adafruit_kb2040picoprobe.upload.maximum_size=8388608
+adafruit_kb2040picoprobe.upload.maximum_data_size=262144
+adafruit_kb2040picoprobe.upload.wait_for_upload_port=true
+adafruit_kb2040picoprobe.upload.erase_cmd=
+adafruit_kb2040picoprobe.serial.disableDTR=false
+adafruit_kb2040picoprobe.serial.disableRTS=false
+adafruit_kb2040picoprobe.build.f_cpu=125000000
+adafruit_kb2040picoprobe.build.led=
+adafruit_kb2040picoprobe.build.core=rp2040
+adafruit_kb2040picoprobe.build.ldscript=memmap_default.ld
+adafruit_kb2040picoprobe.build.ram_length=256k
+adafruit_kb2040picoprobe.build.boot2=boot2_w25q080_2_padded_checksum
+adafruit_kb2040picoprobe.build.vid=0x239a
+adafruit_kb2040picoprobe.build.pid=0x8105
+adafruit_kb2040picoprobe.build.usb_manufacturer="Adafruit"
+adafruit_kb2040picoprobe.build.usb_product="KB2040 (Picoprobe)"
+adafruit_kb2040picoprobe.menu.flash.8388608_0=8MB (no FS)
+adafruit_kb2040picoprobe.menu.flash.8388608_0.upload.maximum_size=8384512
+adafruit_kb2040picoprobe.menu.flash.8388608_0.build.flash_length=8384512
+adafruit_kb2040picoprobe.menu.flash.8388608_0.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_0.build.fs_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_0.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_65536=8MB (Sketch: 8128KB, FS: 64KB)
+adafruit_kb2040picoprobe.menu.flash.8388608_65536.upload.maximum_size=8318976
+adafruit_kb2040picoprobe.menu.flash.8388608_65536.build.flash_length=8318976
+adafruit_kb2040picoprobe.menu.flash.8388608_65536.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_65536.build.fs_start=276754432
+adafruit_kb2040picoprobe.menu.flash.8388608_65536.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_131072=8MB (Sketch: 8064KB, FS: 128KB)
+adafruit_kb2040picoprobe.menu.flash.8388608_131072.upload.maximum_size=8253440
+adafruit_kb2040picoprobe.menu.flash.8388608_131072.build.flash_length=8253440
+adafruit_kb2040picoprobe.menu.flash.8388608_131072.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_131072.build.fs_start=276688896
+adafruit_kb2040picoprobe.menu.flash.8388608_131072.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_262144=8MB (Sketch: 7936KB, FS: 256KB)
+adafruit_kb2040picoprobe.menu.flash.8388608_262144.upload.maximum_size=8122368
+adafruit_kb2040picoprobe.menu.flash.8388608_262144.build.flash_length=8122368
+adafruit_kb2040picoprobe.menu.flash.8388608_262144.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_262144.build.fs_start=276557824
+adafruit_kb2040picoprobe.menu.flash.8388608_262144.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_524288=8MB (Sketch: 7680KB, FS: 512KB)
+adafruit_kb2040picoprobe.menu.flash.8388608_524288.upload.maximum_size=7860224
+adafruit_kb2040picoprobe.menu.flash.8388608_524288.build.flash_length=7860224
+adafruit_kb2040picoprobe.menu.flash.8388608_524288.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_524288.build.fs_start=276295680
+adafruit_kb2040picoprobe.menu.flash.8388608_524288.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576=8MB (Sketch: 7MB, FS: 1MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576.upload.maximum_size=7335936
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576.build.flash_length=7335936
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576.build.fs_start=275771392
+adafruit_kb2040picoprobe.menu.flash.8388608_1048576.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152=8MB (Sketch: 6MB, FS: 2MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152.upload.maximum_size=6287360
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152.build.flash_length=6287360
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152.build.fs_start=274722816
+adafruit_kb2040picoprobe.menu.flash.8388608_2097152.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728=8MB (Sketch: 5MB, FS: 3MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728.upload.maximum_size=5238784
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728.build.flash_length=5238784
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728.build.fs_start=273674240
+adafruit_kb2040picoprobe.menu.flash.8388608_3145728.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304=8MB (Sketch: 4MB, FS: 4MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304.upload.maximum_size=4190208
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304.build.flash_length=4190208
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304.build.fs_start=272625664
+adafruit_kb2040picoprobe.menu.flash.8388608_4194304.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880=8MB (Sketch: 3MB, FS: 5MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880.upload.maximum_size=3141632
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880.build.flash_length=3141632
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880.build.fs_start=271577088
+adafruit_kb2040picoprobe.menu.flash.8388608_5242880.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456=8MB (Sketch: 2MB, FS: 6MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456.upload.maximum_size=2093056
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456.build.flash_length=2093056
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456.build.fs_start=270528512
+adafruit_kb2040picoprobe.menu.flash.8388608_6291456.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032=8MB (Sketch: 1MB, FS: 7MB)
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032.upload.maximum_size=1044480
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032.build.flash_length=1044480
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032.build.eeprom_start=276819968
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032.build.fs_start=269479936
+adafruit_kb2040picoprobe.menu.flash.8388608_7340032.build.fs_end=276819968
+adafruit_kb2040picoprobe.menu.freq.125=125 MHz
+adafruit_kb2040picoprobe.menu.freq.125.build.f_cpu=125000000L
+adafruit_kb2040picoprobe.menu.freq.50=50 MHz
+adafruit_kb2040picoprobe.menu.freq.50.build.f_cpu=50000000L
+adafruit_kb2040picoprobe.menu.freq.100=100 MHz
+adafruit_kb2040picoprobe.menu.freq.100.build.f_cpu=100000000L
+adafruit_kb2040picoprobe.menu.freq.133=133 MHz
+adafruit_kb2040picoprobe.menu.freq.133.build.f_cpu=133000000L
+adafruit_kb2040picoprobe.menu.freq.150=150 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.150.build.f_cpu=150000000L
+adafruit_kb2040picoprobe.menu.freq.175=175 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.175.build.f_cpu=175000000L
+adafruit_kb2040picoprobe.menu.freq.200=200 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.200.build.f_cpu=200000000L
+adafruit_kb2040picoprobe.menu.freq.225=225 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.225.build.f_cpu=225000000L
+adafruit_kb2040picoprobe.menu.freq.250=250 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.250.build.f_cpu=250000000L
+adafruit_kb2040picoprobe.menu.freq.275=275 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.275.build.f_cpu=275000000L
+adafruit_kb2040picoprobe.menu.freq.300=300 MHz (Overclock)
+adafruit_kb2040picoprobe.menu.freq.300.build.f_cpu=300000000L
+adafruit_kb2040picoprobe.menu.opt.Small=Small (-Os) (standard)
+adafruit_kb2040picoprobe.menu.opt.Small.build.flags.optimize=-Os
+adafruit_kb2040picoprobe.menu.opt.Optimize=Optimize (-O)
+adafruit_kb2040picoprobe.menu.opt.Optimize.build.flags.optimize=-O
+adafruit_kb2040picoprobe.menu.opt.Optimize2=Optimize More (-O2)
+adafruit_kb2040picoprobe.menu.opt.Optimize2.build.flags.optimize=-O2
+adafruit_kb2040picoprobe.menu.opt.Optimize3=Optimize Even More (-O3)
+adafruit_kb2040picoprobe.menu.opt.Optimize3.build.flags.optimize=-O3
+adafruit_kb2040picoprobe.menu.opt.Fast=Fast (-Ofast) (maybe slower)
+adafruit_kb2040picoprobe.menu.opt.Fast.build.flags.optimize=-Ofast
+adafruit_kb2040picoprobe.menu.opt.Debug=Debug (-Og)
+adafruit_kb2040picoprobe.menu.opt.Debug.build.flags.optimize=-Og
+adafruit_kb2040picoprobe.menu.rtti.Disabled=Disabled
+adafruit_kb2040picoprobe.menu.rtti.Disabled.build.flags.rtti=-fno-rtti
+adafruit_kb2040picoprobe.menu.rtti.Enabled=Enabled
+adafruit_kb2040picoprobe.menu.rtti.Enabled.build.flags.rtti=
+adafruit_kb2040picoprobe.menu.dbgport.Disabled=Disabled
+adafruit_kb2040picoprobe.menu.dbgport.Disabled.build.debug_port=
+adafruit_kb2040picoprobe.menu.dbgport.Serial=Serial
+adafruit_kb2040picoprobe.menu.dbgport.Serial.build.debug_port=-DDEBUG_RP2040_PORT=Serial
+adafruit_kb2040picoprobe.menu.dbgport.Serial1=Serial1
+adafruit_kb2040picoprobe.menu.dbgport.Serial1.build.debug_port=-DDEBUG_RP2040_PORT=Serial1
+adafruit_kb2040picoprobe.menu.dbgport.Serial2=Serial2
+adafruit_kb2040picoprobe.menu.dbgport.Serial2.build.debug_port=-DDEBUG_RP2040_PORT=Serial2
+adafruit_kb2040picoprobe.menu.dbglvl.None=None
+adafruit_kb2040picoprobe.menu.dbglvl.None.build.debug_level=
+adafruit_kb2040picoprobe.menu.dbglvl.Core=Core
+adafruit_kb2040picoprobe.menu.dbglvl.Core.build.debug_level=-DDEBUG_RP2040_CORE
+adafruit_kb2040picoprobe.menu.dbglvl.SPI=SPI
+adafruit_kb2040picoprobe.menu.dbglvl.SPI.build.debug_level=-DDEBUG_RP2040_SPI
+adafruit_kb2040picoprobe.menu.dbglvl.Wire=Wire
+adafruit_kb2040picoprobe.menu.dbglvl.Wire.build.debug_level=-DDEBUG_RP2040_WIRE
+adafruit_kb2040picoprobe.menu.dbglvl.All=All
+adafruit_kb2040picoprobe.menu.dbglvl.All.build.debug_level=-DDEBUG_RP2040_WIRE -DDEBUG_RP2040_SPI -DDEBUG_RP2040_CORE
+adafruit_kb2040picoprobe.menu.dbglvl.NDEBUG=NDEBUG
+adafruit_kb2040picoprobe.menu.dbglvl.NDEBUG.build.debug_level=-DNDEBUG
+adafruit_kb2040picoprobe.menu.usbstack.picosdk=Pico SDK
+adafruit_kb2040picoprobe.menu.usbstack.picosdk.build.usbstack_flags="-I{runtime.platform.path}/tools/libpico"
+adafruit_kb2040picoprobe.menu.usbstack.tinyusb=Adafruit TinyUSB
+adafruit_kb2040picoprobe.menu.usbstack.tinyusb.build.usbstack_flags=-DUSE_TINYUSB "-I{runtime.platform.path}/libraries/Adafruit_TinyUSB_Arduino/src/arduino"
+
+# -----------------------------------
+# Adafruit KB2040 (pico-debug)
+# -----------------------------------
+adafruit_kb2040picodebug.name=Adafruit KB2040 (pico-debug)
+adafruit_kb2040picodebug.vid.0=0x1209
+adafruit_kb2040picodebug.pid.0=0x2488
+adafruit_kb2040picodebug.build.usbpid=-DSERIALUSB_PID=0x8105
+adafruit_kb2040picodebug.build.usbpwr=-DUSBD_MAX_POWER_MA=250
+adafruit_kb2040picodebug.build.board=ADAFRUIT_KB2040_RP2040
+adafruit_kb2040picodebug.build.mcu=cortex-m0plus
+adafruit_kb2040picodebug.build.variant=adafruit_kb2040
+adafruit_kb2040picodebug.upload.tool=picodebug
+adafruit_kb2040picodebug.upload.maximum_size=8388608
+adafruit_kb2040picodebug.upload.maximum_data_size=245760
+adafruit_kb2040picodebug.upload.wait_for_upload_port=true
+adafruit_kb2040picodebug.upload.erase_cmd=
+adafruit_kb2040picodebug.serial.disableDTR=false
+adafruit_kb2040picodebug.serial.disableRTS=false
+adafruit_kb2040picodebug.build.f_cpu=125000000
+adafruit_kb2040picodebug.build.led=
+adafruit_kb2040picodebug.build.core=rp2040
+adafruit_kb2040picodebug.build.ldscript=memmap_default.ld
+adafruit_kb2040picodebug.build.ram_length=240k
+adafruit_kb2040picodebug.build.boot2=boot2_w25q080_2_padded_checksum
+adafruit_kb2040picodebug.build.vid=0x239a
+adafruit_kb2040picodebug.build.pid=0x8105
+adafruit_kb2040picodebug.build.usb_manufacturer="Adafruit"
+adafruit_kb2040picodebug.build.usb_product="KB2040 (pico-debug)"
+adafruit_kb2040picodebug.menu.flash.8388608_0=8MB (no FS)
+adafruit_kb2040picodebug.menu.flash.8388608_0.upload.maximum_size=8384512
+adafruit_kb2040picodebug.menu.flash.8388608_0.build.flash_length=8384512
+adafruit_kb2040picodebug.menu.flash.8388608_0.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_0.build.fs_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_0.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_65536=8MB (Sketch: 8128KB, FS: 64KB)
+adafruit_kb2040picodebug.menu.flash.8388608_65536.upload.maximum_size=8318976
+adafruit_kb2040picodebug.menu.flash.8388608_65536.build.flash_length=8318976
+adafruit_kb2040picodebug.menu.flash.8388608_65536.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_65536.build.fs_start=276754432
+adafruit_kb2040picodebug.menu.flash.8388608_65536.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_131072=8MB (Sketch: 8064KB, FS: 128KB)
+adafruit_kb2040picodebug.menu.flash.8388608_131072.upload.maximum_size=8253440
+adafruit_kb2040picodebug.menu.flash.8388608_131072.build.flash_length=8253440
+adafruit_kb2040picodebug.menu.flash.8388608_131072.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_131072.build.fs_start=276688896
+adafruit_kb2040picodebug.menu.flash.8388608_131072.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_262144=8MB (Sketch: 7936KB, FS: 256KB)
+adafruit_kb2040picodebug.menu.flash.8388608_262144.upload.maximum_size=8122368
+adafruit_kb2040picodebug.menu.flash.8388608_262144.build.flash_length=8122368
+adafruit_kb2040picodebug.menu.flash.8388608_262144.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_262144.build.fs_start=276557824
+adafruit_kb2040picodebug.menu.flash.8388608_262144.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_524288=8MB (Sketch: 7680KB, FS: 512KB)
+adafruit_kb2040picodebug.menu.flash.8388608_524288.upload.maximum_size=7860224
+adafruit_kb2040picodebug.menu.flash.8388608_524288.build.flash_length=7860224
+adafruit_kb2040picodebug.menu.flash.8388608_524288.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_524288.build.fs_start=276295680
+adafruit_kb2040picodebug.menu.flash.8388608_524288.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_1048576=8MB (Sketch: 7MB, FS: 1MB)
+adafruit_kb2040picodebug.menu.flash.8388608_1048576.upload.maximum_size=7335936
+adafruit_kb2040picodebug.menu.flash.8388608_1048576.build.flash_length=7335936
+adafruit_kb2040picodebug.menu.flash.8388608_1048576.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_1048576.build.fs_start=275771392
+adafruit_kb2040picodebug.menu.flash.8388608_1048576.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_2097152=8MB (Sketch: 6MB, FS: 2MB)
+adafruit_kb2040picodebug.menu.flash.8388608_2097152.upload.maximum_size=6287360
+adafruit_kb2040picodebug.menu.flash.8388608_2097152.build.flash_length=6287360
+adafruit_kb2040picodebug.menu.flash.8388608_2097152.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_2097152.build.fs_start=274722816
+adafruit_kb2040picodebug.menu.flash.8388608_2097152.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_3145728=8MB (Sketch: 5MB, FS: 3MB)
+adafruit_kb2040picodebug.menu.flash.8388608_3145728.upload.maximum_size=5238784
+adafruit_kb2040picodebug.menu.flash.8388608_3145728.build.flash_length=5238784
+adafruit_kb2040picodebug.menu.flash.8388608_3145728.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_3145728.build.fs_start=273674240
+adafruit_kb2040picodebug.menu.flash.8388608_3145728.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_4194304=8MB (Sketch: 4MB, FS: 4MB)
+adafruit_kb2040picodebug.menu.flash.8388608_4194304.upload.maximum_size=4190208
+adafruit_kb2040picodebug.menu.flash.8388608_4194304.build.flash_length=4190208
+adafruit_kb2040picodebug.menu.flash.8388608_4194304.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_4194304.build.fs_start=272625664
+adafruit_kb2040picodebug.menu.flash.8388608_4194304.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_5242880=8MB (Sketch: 3MB, FS: 5MB)
+adafruit_kb2040picodebug.menu.flash.8388608_5242880.upload.maximum_size=3141632
+adafruit_kb2040picodebug.menu.flash.8388608_5242880.build.flash_length=3141632
+adafruit_kb2040picodebug.menu.flash.8388608_5242880.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_5242880.build.fs_start=271577088
+adafruit_kb2040picodebug.menu.flash.8388608_5242880.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_6291456=8MB (Sketch: 2MB, FS: 6MB)
+adafruit_kb2040picodebug.menu.flash.8388608_6291456.upload.maximum_size=2093056
+adafruit_kb2040picodebug.menu.flash.8388608_6291456.build.flash_length=2093056
+adafruit_kb2040picodebug.menu.flash.8388608_6291456.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_6291456.build.fs_start=270528512
+adafruit_kb2040picodebug.menu.flash.8388608_6291456.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_7340032=8MB (Sketch: 1MB, FS: 7MB)
+adafruit_kb2040picodebug.menu.flash.8388608_7340032.upload.maximum_size=1044480
+adafruit_kb2040picodebug.menu.flash.8388608_7340032.build.flash_length=1044480
+adafruit_kb2040picodebug.menu.flash.8388608_7340032.build.eeprom_start=276819968
+adafruit_kb2040picodebug.menu.flash.8388608_7340032.build.fs_start=269479936
+adafruit_kb2040picodebug.menu.flash.8388608_7340032.build.fs_end=276819968
+adafruit_kb2040picodebug.menu.freq.125=125 MHz
+adafruit_kb2040picodebug.menu.freq.125.build.f_cpu=125000000L
+adafruit_kb2040picodebug.menu.freq.50=50 MHz
+adafruit_kb2040picodebug.menu.freq.50.build.f_cpu=50000000L
+adafruit_kb2040picodebug.menu.freq.100=100 MHz
+adafruit_kb2040picodebug.menu.freq.100.build.f_cpu=100000000L
+adafruit_kb2040picodebug.menu.freq.133=133 MHz
+adafruit_kb2040picodebug.menu.freq.133.build.f_cpu=133000000L
+adafruit_kb2040picodebug.menu.freq.150=150 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.150.build.f_cpu=150000000L
+adafruit_kb2040picodebug.menu.freq.175=175 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.175.build.f_cpu=175000000L
+adafruit_kb2040picodebug.menu.freq.200=200 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.200.build.f_cpu=200000000L
+adafruit_kb2040picodebug.menu.freq.225=225 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.225.build.f_cpu=225000000L
+adafruit_kb2040picodebug.menu.freq.250=250 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.250.build.f_cpu=250000000L
+adafruit_kb2040picodebug.menu.freq.275=275 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.275.build.f_cpu=275000000L
+adafruit_kb2040picodebug.menu.freq.300=300 MHz (Overclock)
+adafruit_kb2040picodebug.menu.freq.300.build.f_cpu=300000000L
+adafruit_kb2040picodebug.menu.opt.Small=Small (-Os) (standard)
+adafruit_kb2040picodebug.menu.opt.Small.build.flags.optimize=-Os
+adafruit_kb2040picodebug.menu.opt.Optimize=Optimize (-O)
+adafruit_kb2040picodebug.menu.opt.Optimize.build.flags.optimize=-O
+adafruit_kb2040picodebug.menu.opt.Optimize2=Optimize More (-O2)
+adafruit_kb2040picodebug.menu.opt.Optimize2.build.flags.optimize=-O2
+adafruit_kb2040picodebug.menu.opt.Optimize3=Optimize Even More (-O3)
+adafruit_kb2040picodebug.menu.opt.Optimize3.build.flags.optimize=-O3
+adafruit_kb2040picodebug.menu.opt.Fast=Fast (-Ofast) (maybe slower)
+adafruit_kb2040picodebug.menu.opt.Fast.build.flags.optimize=-Ofast
+adafruit_kb2040picodebug.menu.opt.Debug=Debug (-Og)
+adafruit_kb2040picodebug.menu.opt.Debug.build.flags.optimize=-Og
+adafruit_kb2040picodebug.menu.rtti.Disabled=Disabled
+adafruit_kb2040picodebug.menu.rtti.Disabled.build.flags.rtti=-fno-rtti
+adafruit_kb2040picodebug.menu.rtti.Enabled=Enabled
+adafruit_kb2040picodebug.menu.rtti.Enabled.build.flags.rtti=
+adafruit_kb2040picodebug.menu.dbgport.Disabled=Disabled
+adafruit_kb2040picodebug.menu.dbgport.Disabled.build.debug_port=
+adafruit_kb2040picodebug.menu.dbgport.Serial=Serial
+adafruit_kb2040picodebug.menu.dbgport.Serial.build.debug_port=-DDEBUG_RP2040_PORT=Serial
+adafruit_kb2040picodebug.menu.dbgport.Serial1=Serial1
+adafruit_kb2040picodebug.menu.dbgport.Serial1.build.debug_port=-DDEBUG_RP2040_PORT=Serial1
+adafruit_kb2040picodebug.menu.dbgport.Serial2=Serial2
+adafruit_kb2040picodebug.menu.dbgport.Serial2.build.debug_port=-DDEBUG_RP2040_PORT=Serial2
+adafruit_kb2040picodebug.menu.dbglvl.None=None
+adafruit_kb2040picodebug.menu.dbglvl.None.build.debug_level=
+adafruit_kb2040picodebug.menu.dbglvl.Core=Core
+adafruit_kb2040picodebug.menu.dbglvl.Core.build.debug_level=-DDEBUG_RP2040_CORE
+adafruit_kb2040picodebug.menu.dbglvl.SPI=SPI
+adafruit_kb2040picodebug.menu.dbglvl.SPI.build.debug_level=-DDEBUG_RP2040_SPI
+adafruit_kb2040picodebug.menu.dbglvl.Wire=Wire
+adafruit_kb2040picodebug.menu.dbglvl.Wire.build.debug_level=-DDEBUG_RP2040_WIRE
+adafruit_kb2040picodebug.menu.dbglvl.All=All
+adafruit_kb2040picodebug.menu.dbglvl.All.build.debug_level=-DDEBUG_RP2040_WIRE -DDEBUG_RP2040_SPI -DDEBUG_RP2040_CORE
+adafruit_kb2040picodebug.menu.dbglvl.NDEBUG=NDEBUG
+adafruit_kb2040picodebug.menu.dbglvl.NDEBUG.build.debug_level=-DNDEBUG
+adafruit_kb2040picodebug.menu.usbstack.nousb=No USB
+adafruit_kb2040picodebug.menu.usbstack.nousb.build.usbstack_flags="-DNO_USB -DDISABLE_USB_SERIAL -I{runtime.platform.path}/tools/libpico"
+
 # -----------------------------------
 # Arduino Nano RP2040 Connect
 # -----------------------------------

cores/rp2040/Arduino.h

@@ -97,6 +97,7 @@ void analogWriteResolution(int res);
 
 #include "SerialUART.h"
 #include "RP2040Support.h"
+#include "SerialPIO.h"
 #include "Bootsel.h"
 
 // Template which will evaluate at *compile time* to a single 32b number

cores/rp2040/SerialPIO.cpp

@@ -0,0 +1,338 @@
+/*
+    Serial-over-PIO for the Raspberry Pi Pico RP2040
+
+    Copyright (c) 2021 Earle F. Philhower, III <earlephilhower@yahoo.com>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "SerialPIO.h"
+#include "CoreMutex.h"
+#include <hardware/gpio.h>
+#include <map>
+#include "pio_uart.pio.h"
+
+
+// ------------------------------------------------------------------------
+// -- Generates a unique program for differing bit lengths
+static std::map<int, PIOProgram*> _txMap;
+static std::map<int, PIOProgram*> _rxMap;
+
+// Duplicate a program and replace the first insn with a "set x, repl"
+static pio_program_t *pio_make_uart_prog(int repl, const pio_program_t *pg) {
+    pio_program_t *p = new pio_program_t;
+    p->length = pg->length;
+    p->origin = pg->origin;
+    uint16_t *insn = (uint16_t *)malloc(p->length * 2);
+    memcpy(insn, pg->instructions, p->length * 2);
+    insn[0] = pio_encode_set(pio_x, repl);
+    p->instructions = insn;
+    return p;
+}
+
+static PIOProgram *_getTxProgram(int bits) {
+    auto f = _txMap.find(bits);
+    if (f == _txMap.end()) {
+        pio_program_t * p = pio_make_uart_prog(bits, &pio_tx_program);
+        _txMap.insert({bits, new PIOProgram(p)});
+        f = _txMap.find(bits);
+    }
+    return f->second;
+}
+
+static PIOProgram *_getRxProgram(int bits) {
+    auto f = _rxMap.find(bits);
+    if (f == _rxMap.end()) {
+        pio_program_t * p = pio_make_uart_prog(bits, &pio_rx_program);
+        _rxMap.insert({bits, new PIOProgram(p)});
+        f = _rxMap.find(bits);
+    }
+    return f->second;
+}
+// ------------------------------------------------------------------------
+
+// TODO - this works, but there must be a faster/better way...
+static int _parity(int bits, int data) {
+    int p = 0;
+    for (int b = 0; b < bits; b++) {
+        p ^= (data & (1 << b)) ? 1 : 0;
+    }
+    return p;
+}
+
+// We need to cache generated SerialPIOs so we can add data to them from
+// the shared handler
+static SerialPIO *_pioSP[2][4];
+static void __not_in_flash_func(_fifoIRQ)() {
+    for (int p = 0; p < 2; p++) {
+        for (int sm = 0; sm < 4; sm++) {
+            SerialPIO *s = _pioSP[p][sm];
+            if (s) {
+                s->_handleIRQ();
+                pio_interrupt_clear((p == 0) ? pio0 : pio1, sm);
+            }
+        }
+    }
+}
+
+void __not_in_flash_func(SerialPIO::_handleIRQ)() {
+    if (_rx == NOPIN) {
+        return;
+    }
+    while (!pio_sm_is_rx_fifo_empty(_rxPIO, _rxSM)) {
+        uint32_t decode = _rxPIO->rxf[_rxSM];
+        decode >>= 32 - _rxBits;
+        uint32_t val = 0;
+        for (int b = 0; b < _bits + 1; b++) {
+            val |= (decode & (1 << (b * 2))) ? 1 << b : 0;
+        }
+        if (_parity == UART_PARITY_EVEN) {
+            int p = ::_parity(_bits, val);
+            int r = (val & (1 << _bits)) ? 1 : 0;
+            if (p != r) {
+                // TODO - parity error
+                continue;
+            }
+        } else if (_parity == UART_PARITY_ODD) {
+            int p = ::_parity(_bits, val);
+            int r = (val & (1 << _bits)) ? 1 : 0;
+            if (p == r) {
+                // TODO - parity error
+                continue;
+            }
+        }
+
+        if ((_writer + 1) % sizeof(_queue) != _reader) {
+            _queue[_writer] = val & ((1 << _bits) -  1);
+            asm volatile("" ::: "memory"); // Ensure the queue is written before the written count advances
+            _writer = (_writer + 1) % sizeof(_queue);
+        } else {
+            // TODO: Overflow
+        }
+    }
+}
+
+SerialPIO::SerialPIO(pin_size_t tx, pin_size_t rx) {
+    _tx = tx;
+    _rx = rx;
+    mutex_init(&_mutex);
+}
+
+void SerialPIO::begin(unsigned long baud, uint16_t config) {
+    _baud = baud;
+    switch (config & SERIAL_PARITY_MASK) {
+    case SERIAL_PARITY_EVEN:
+        _parity = UART_PARITY_EVEN;
+        break;
+    case SERIAL_PARITY_ODD:
+        _parity = UART_PARITY_ODD;
+        break;
+    default:
+        _parity = UART_PARITY_NONE;
+        break;
+    }
+    switch (config & SERIAL_STOP_BIT_MASK) {
+    case SERIAL_STOP_BIT_1:
+        _stop = 1;
+        break;
+    default:
+        _stop = 2;
+        break;
+    }
+    switch (config & SERIAL_DATA_MASK) {
+    case SERIAL_DATA_5:
+        _bits = 5;
+        break;
+    case SERIAL_DATA_6:
+        _bits = 6;
+        break;
+    case SERIAL_DATA_7:
+        _bits = 7;
+        break;
+    default:
+        _bits = 8;
+        break;
+    }
+
+    if ((_tx == NOPIN) && (_rx == NOPIN)) {
+        DEBUGCORE("ERROR: No pins specified for SerialPIO\n");
+        return;
+    }
+
+    if (_tx != NOPIN) {
+        _txBits = _bits + _stop + (_parity != UART_PARITY_NONE ? 1 : 0) + 1/*start bit*/;
+        _txPgm = _getTxProgram(_txBits);
+        int off;
+        if (!_txPgm->prepare(&_txPIO, &_txSM, &off)) {
+            DEBUGCORE("ERROR: Unable to allocate PIO TX UART, out of PIO resources\n");
+            // ERROR, no free slots
+            return;
+        }
+
+        digitalWrite(_tx, HIGH);
+        pinMode(_tx, OUTPUT);
+
+        pio_tx_program_init(_txPIO, _txSM, off, _tx);
+        pio_sm_clear_fifos(_txPIO, _txSM); // Remove any existing data
+
+        // Put the divider into ISR w/o using up program space
+        pio_sm_put_blocking(_txPIO, _txSM, clock_get_hz(clk_sys) / _baud - 2);
+        pio_sm_exec(_txPIO, _txSM, pio_encode_pull(false, false));
+        pio_sm_exec(_txPIO, _txSM, pio_encode_mov(pio_isr, pio_osr));
+
+        // Start running!
+        pio_sm_set_enabled(_txPIO, _txSM, true);
+    }
+    if (_rx != NOPIN) {
+        _writer = 0;
+        _reader = 0;
+
+        _rxBits = 2 * (_bits + _stop + (_parity != UART_PARITY_NONE ? 1 : 0) + 1) - 1;
+        _rxPgm = _getRxProgram(_rxBits);
+        int off;
+        if (!_rxPgm->prepare(&_rxPIO, &_rxSM, &off)) {
+            DEBUGCORE("ERROR: Unable to allocate PIO RX UART, out of PIO resources\n");
+            return;
+        }
+        // Stash away the created RX port for the IRQ handler
+        _pioSP[pio_get_index(_rxPIO)][_rxSM] = this;
+
+        pinMode(_rx, INPUT);
+        pio_rx_program_init(_rxPIO, _rxSM, off, _rx);
+        pio_sm_clear_fifos(_rxPIO, _rxSM); // Remove any existing data
+
+        // Put phase divider into OSR w/o using add'l program memory
+        pio_sm_put_blocking(_rxPIO, _rxSM, clock_get_hz(clk_sys) / (_baud * 2) - 2);
+        pio_sm_exec(_rxPIO, _rxSM, pio_encode_pull(false, false));
+
+        // Join the TX FIFO to the RX one now that we don't need it
+        _rxPIO->sm[_rxSM].shiftctrl |= 0x80000000;
+
+        // Enable interrupts on rxfifo
+        switch (_rxSM) {
+        case 0: pio_set_irq0_source_enabled(_rxPIO, pis_sm0_rx_fifo_not_empty, true); break;
+        case 1: pio_set_irq0_source_enabled(_rxPIO, pis_sm1_rx_fifo_not_empty, true); break;
+        case 2: pio_set_irq0_source_enabled(_rxPIO, pis_sm2_rx_fifo_not_empty, true); break;
+        case 3: pio_set_irq0_source_enabled(_rxPIO, pis_sm3_rx_fifo_not_empty, true); break;
+        }
+        irq_set_exclusive_handler(PIO0_IRQ_0, _fifoIRQ);
+        irq_set_enabled(PIO0_IRQ_0, true);
+
+        pio_sm_set_enabled(_rxPIO, _rxSM, true);
+    }
+
+    _running = true;
+}
+
+void SerialPIO::end() {
+    if (!_running) {
+        return;
+    }
+    // TODO: Deallocate PIO resources, stop them
+    _pioSP[pio_get_index(_rxPIO)][_rxSM] = nullptr;
+    _running = false;
+}
+
+int SerialPIO::peek() {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_rx == NOPIN)) {
+        return -1;
+    }
+    // If there's something in the FIFO now, just peek at it
+    uint32_t start = millis();
+    uint32_t now = millis();
+    while ((now - start) < _timeout) {
+        if (_writer != _reader) {
+            return _queue[_reader];
+        }
+        delay(1);
+        now = millis();
+    }
+    return -1; // Nothing available before timeout
+}
+
+int SerialPIO::read() {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_rx == NOPIN)) {
+        return -1;
+    }
+    uint32_t start = millis();
+    uint32_t now = millis();
+    while ((now - start) < _timeout) {
+        if (_writer != _reader) {
+            auto ret = _queue[_reader];
+            _reader = (_reader + 1) % sizeof(_queue);
+            return ret;
+        }
+        delay(1);
+        now = millis();
+    }
+    return -1; // Timeout
+}
+
+int SerialPIO::available() {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_rx == NOPIN)) {
+        return 0;
+    }
+    return (_writer - _reader) % sizeof(_queue);
+}
+
+int SerialPIO::availableForWrite() {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_tx == NOPIN)) {
+        return 0;
+    }
+    return 8 - pio_sm_get_tx_fifo_level(_txPIO, _txSM);
+}
+
+void SerialPIO::flush() {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_tx == NOPIN)) {
+        return;
+    }
+    while (!pio_sm_is_tx_fifo_empty(_txPIO, _txSM)) {
+        delay(1); // Wait for all FIFO to be read
+    }
+    // Could have 1 byte being transmitted, so wait for bit times
+    delay((1000 * (_txBits + 1)) / _baud);
+}
+
+size_t SerialPIO::write(uint8_t c) {
+    CoreMutex m(&_mutex);
+    if (!_running || !m || (_tx == NOPIN)) {
+        return 0;
+    }
+
+    uint32_t val = c;
+    if (_parity == UART_PARITY_NONE) {
+        val |= 7 << _bits; // Set 2 stop bits, the HW will only transmit the required number
+    } else if (_parity == UART_PARITY_EVEN) {
+        val |= ::_parity(_bits, c) << _bits;
+        val |= 7 << (_bits + 1);
+    } else {
+        val |= (1 ^ ::_parity(_bits, c)) << _bits;
+        val |= 7 << (_bits + 1);
+    }
+    val <<= 1;  // Start bit = low
+
+    pio_sm_put_blocking(_txPIO, _txSM, val);
+
+    return 1;
+}
+
+SerialPIO::operator bool() {
+    return _running;
+}

cores/rp2040/SerialPIO.h

@@ -0,0 +1,78 @@
+/*
+    Serial-over-PIO for the Raspberry Pi Pico RP2040
+
+    Copyright (c) 2021 Earle F. Philhower, III <earlephilhower@yahoo.com>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#pragma once
+
+#include <Arduino.h>
+#include "api/HardwareSerial.h"
+#include <stdarg.h>
+#include <queue>
+#include <hardware/uart.h>
+#include "CoreMutex.h"
+
+extern "C" typedef struct uart_inst uart_inst_t;
+
+class SerialPIO : public HardwareSerial {
+public:
+    static const pin_size_t NOPIN = 0xff; // Use in constructor to disable RX or TX unit
+    SerialPIO(pin_size_t tx, pin_size_t rx);
+
+    void begin(unsigned long baud = 115200) override {
+        begin(baud, SERIAL_8N1);
+    };
+    void begin(unsigned long baud, uint16_t config) override;
+    void end() override;
+
+    virtual int peek() override;
+    virtual int read() override;
+    virtual int available() override;
+    virtual int availableForWrite() override;
+    virtual void flush() override;
+    virtual size_t write(uint8_t c) override;
+    using Print::write;
+    operator bool() override;
+
+    // Not to be called by users, only from the IRQ handler.  In public so that the C-language IQR callback can access it
+    void _handleIRQ();
+
+private:
+    bool _running = false;
+    pin_size_t _tx, _rx;
+    int _baud;
+    int _bits;
+    uart_parity_t _parity;
+    int _stop;
+    mutex_t _mutex;
+
+    PIOProgram *_txPgm;
+    PIO _txPIO;
+    int _txSM;
+    int _txBits;
+
+    PIOProgram *_rxPgm;
+    PIO _rxPIO;
+    int _rxSM;
+    int _rxBits;
+
+    // Lockless, IRQ-handled circular queue
+    uint32_t _writer;
+    uint32_t _reader;
+    uint8_t  _queue[32];
+};

cores/rp2040/SerialUART.cpp

@@ -72,65 +72,90 @@ SerialUART::SerialUART(uart_inst_t *uart, pin_size_t tx, pin_size_t rx) {
     mutex_init(&_mutex);
 }
 
+static void _uart0IRQ();
+static void _uart1IRQ();
+
 void SerialUART::begin(unsigned long baud, uint16_t config) {
     _baud = baud;
     uart_init(_uart, baud);
     int bits, stop;
     uart_parity_t parity;
     switch (config & SERIAL_PARITY_MASK) {
-    case SERIAL_PARITY_EVEN: parity = UART_PARITY_EVEN; break;
-    case SERIAL_PARITY_ODD: parity = UART_PARITY_ODD; break;
-    default: parity = UART_PARITY_NONE; break;
+    case SERIAL_PARITY_EVEN:
+        parity = UART_PARITY_EVEN;
+        break;
+    case SERIAL_PARITY_ODD:
+        parity = UART_PARITY_ODD;
+        break;
+    default:
+        parity = UART_PARITY_NONE;
+        break;
     }
     switch (config & SERIAL_STOP_BIT_MASK) {
-    case SERIAL_STOP_BIT_1: stop = 1; break;
-    default: stop = 2; break;
+    case SERIAL_STOP_BIT_1:
+        stop = 1;
+        break;
+    default:
+        stop = 2;
+        break;
     }
     switch (config & SERIAL_DATA_MASK) {
-    case SERIAL_DATA_5: bits = 5; break;
-    case SERIAL_DATA_6: bits = 6; break;
-    case SERIAL_DATA_7: bits = 7; break;
-    default: bits = 8; break;
+    case SERIAL_DATA_5:
+        bits = 5;
+        break;
+    case SERIAL_DATA_6:
+        bits = 6;
+        break;
+    case SERIAL_DATA_7:
+        bits = 7;
+        break;
+    default:
+        bits = 8;
+        break;
     }
     uart_set_format(_uart, bits, stop, parity);
     gpio_set_function(_tx, GPIO_FUNC_UART);
     gpio_set_function(_rx, GPIO_FUNC_UART);
-    _running = true;
-    while (!_swFIFO.empty()) {
-        (void)_swFIFO.pop(); // Just throw out anything in our old FIFO
+    _writer = 0;
+    _reader = 0;
+
+    if (_uart == uart0) {
+        irq_set_exclusive_handler(UART0_IRQ, _uart0IRQ);
+        irq_set_enabled(UART0_IRQ, true);
+    } else {
+        irq_set_exclusive_handler(UART1_IRQ, _uart1IRQ);
+        irq_set_enabled(UART1_IRQ, true);
     }
+    uart_get_hw(_uart)->imsc |= UART_UARTIMSC_RXIM_BITS | UART_UARTIMSC_RTIM_BITS;
+    _running = true;
 }
 
 void SerialUART::end() {
     if (!_running) {
         return;
     }
+    if (_uart == uart0) {
+        irq_set_enabled(UART0_IRQ, false);
+    } else {
+        irq_set_enabled(UART1_IRQ, false);
+    }
     uart_deinit(_uart);
     _running = false;
 }
 
-// Transfers any data in the HW FIFO into our SW one, up to 32 bytes
-void SerialUART::_pumpFIFO() {
-    while ((_swFIFO.size() < 32) && (uart_is_readable(_uart))) {
-        _swFIFO.push(uart_getc(_uart));
-    }
-}
-
 int SerialUART::peek() {
     CoreMutex m(&_mutex);
     if (!_running || !m) {
         return -1;
     }
-    _pumpFIFO();
-    // If there's something in the FIFO now, just peek at it
-    if (_swFIFO.size()) {
-        return _swFIFO.front();
-    }
-    // The SW FIFO is empty, read the HW one until the timeout
-    if (uart_is_readable_within_us(_uart, _timeout * 1000)) {
-        // We got one char, put it in the FIFO (which will now have exactly 1 byte) and return it
-        _swFIFO.push(uart_getc(_uart));
-        return _swFIFO.front();
+    uint32_t start = millis();
+    uint32_t now = millis();
+    while ((now - start) < _timeout) {
+        if (_writer != _reader) {
+            return _queue[_reader];
+        }
+        delay(1);
+        now = millis();
     }
     return -1; // Nothing available before timeout
 }
@@ -140,16 +165,16 @@ int SerialUART::read() {
     if (!_running || !m) {
         return -1;
     }
-    _pumpFIFO();
-    if (_swFIFO.size()) {
-        auto ret = _swFIFO.front();
-        _swFIFO.pop();
-        return ret;
-    }
-    // The SW FIFO is empty, read the HW one until the timeout
-    if (uart_is_readable_within_us(_uart, _timeout * 1000)) {
-        // We got one char, return it (FIFO will still be empty
-        return uart_getc(_uart);
+    uint32_t start = millis();
+    uint32_t now = millis();
+    while ((now - start) < _timeout) {
+        if (_writer != _reader) {
+            auto ret = _queue[_reader];
+            _reader = (_reader + 1) % sizeof(_queue);
+            return ret;
+        }
+        delay(1);
+        now = millis();
     }
     return -1; // Timeout
 }
@@ -159,8 +184,7 @@ int SerialUART::available() {
     if (!_running || !m) {
         return 0;
     }
-    _pumpFIFO();
-    return _swFIFO.size();
+    return (_writer - _reader) % sizeof(_queue);
 }
 
 int SerialUART::availableForWrite() {
@@ -168,7 +192,6 @@ int SerialUART::availableForWrite() {
     if (!_running || !m) {
         return 0;
     }
-    _pumpFIFO();
     return (uart_is_writable(_uart)) ? 1 : 0;
 }
 
@@ -177,7 +200,6 @@ void SerialUART::flush() {
     if (!_running || !m) {
         return;
     }
-    _pumpFIFO();
     uart_tx_wait_blocking(_uart);
 }
 
@@ -186,7 +208,6 @@ size_t SerialUART::write(uint8_t c) {
     if (!_running || !m) {
         return 0;
     }
-    _pumpFIFO();
     uart_putc_raw(_uart, c);
     return 1;
 }
@@ -196,7 +217,6 @@ size_t SerialUART::write(const uint8_t *p, size_t len) {
     if (!_running || !m) {
         return 0;
     }
-    _pumpFIFO();
     size_t cnt = len;
     while (cnt) {
         uart_putc_raw(_uart, *p);
@@ -224,3 +244,26 @@ void arduino::serialEvent2Run(void) {
         serialEvent2();
     }
 }
+
+// IRQ handler, called when FIFO > 1/4 full or when it had held unread data for >32 bit times
+void __not_in_flash_func(SerialUART::_handleIRQ)() {
+    uart_get_hw(_uart)->icr |= UART_UARTICR_RTIC_BITS | UART_UARTICR_RXIC_BITS;
+    while (uart_is_readable(_uart)) {
+        auto val = uart_getc(_uart);
+        if ((_writer + 1) % sizeof(_queue) != _reader) {
+            _queue[_writer] = val;
+            asm volatile("" ::: "memory"); // Ensure the queue is written before the written count advances
+            _writer = (_writer + 1) % sizeof(_queue);
+        } else {
+            // TODO: Overflow
+        }
+    }
+}
+
+static void __not_in_flash_func(_uart0IRQ)() {
+    Serial1._handleIRQ();
+}
+
+static void __not_in_flash_func(_uart1IRQ)() {
+    Serial2._handleIRQ();
+}

cores/rp2040/SerialUART.h

@@ -57,6 +57,9 @@ public:
     using Print::write;
     operator bool() override;
 
+    // Not to be called by users, only from the IRQ handler.  In public so that the C-language IQR callback can access it
+    void _handleIRQ();
+
 private:
     bool _running = false;
     uart_inst_t *_uart;
@@ -64,8 +67,10 @@ private:
     int _baud;
     mutex_t _mutex;
 
-    void _pumpFIFO();
-    std::queue<uint8_t> _swFIFO;
+    // Lockless, IRQ-handled circular queue
+    uint32_t _writer;
+    uint32_t _reader;
+    uint8_t  _queue[32];
 };
 
 extern SerialUART Serial1; // HW UART 0

cores/rp2040/pio_uart.pio

@@ -0,0 +1,109 @@
+; pio_uart for the Raspberry Pi Pico RP2040
+;
+; Based loosely off of the uart_rx/_tx examples in the pico-examples repo,
+; but heavily modified and optimized to not require changing the PIO
+; clocks so that Tone and Servo won't be affected, and multiple different
+; PIO ports can be run at different baud at the same time.
+;
+; Copyright (c) 2021 Earle F. Philhower, III <earlephilhower@yahoo.com>
+;
+; This library is free software; you can redistribute it and/or
+; modify it under the terms of the GNU Lesser General Public
+; License as published by the Free Software Foundation; either
+; version 2.1 of the License, or (at your option) any later version.
+;
+; This library is distributed in the hope that it will be useful,
+; but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; Lesser General Public License for more details.
+;
+; You should have received a copy of the GNU Lesser General Public
+; License along with this library; if not, write to the Free Software
+; Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+
+
+.program pio_tx
+.side_set 1 opt
+
+; We shift out the start and stop bit as part of the FIFO
+    set x, 9
+
+    pull               side 1 ; Force stop bit
+
+; Send the bits
+bitloop:
+    out pins, 1
+    mov y, isr                ; ISR is loaded by the setup routine with the period-1 count
+wait_bit:
+    jmp y-- wait_bit
+    jmp x-- bitloop
+
+    
+
+% c-sdk {
+
+static inline void pio_tx_program_init(PIO pio, uint sm, uint offset, uint pin_tx) {
+    // Tell PIO to initially drive output-high on the selected pin, then map PIO
+    // onto that pin with the IO muxes.
+    pio_sm_set_pins_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_sm_set_pindirs_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_gpio_init(pio, pin_tx);
+
+    pio_sm_config c = pio_tx_program_get_default_config(offset);
+
+    // OUT shifts to right, no autopull
+    sm_config_set_out_shift(&c, true, false, 32);
+
+    // We are mapping both OUT and side-set to the same pin, because sometimes
+    // we need to assert user data onto the pin (with OUT) and sometimes
+    // assert constant values (start/stop bit)
+    sm_config_set_out_pins(&c, pin_tx, 1);
+    sm_config_set_sideset_pins(&c, pin_tx);
+
+    // We only need TX, so get an 8-deep FIFO!
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+
+    pio_sm_init(pio, sm, offset, &c);
+}
+
+%}
+
+
+.program pio_rx
+
+; IN pin 0 and JMP pin are both mapped to the GPIO used as UART RX.
+
+start:
+    set x, 18           ; Preload bit counter...we'll shift in the start bit and stop bit, and each bit will be double-recorded (to be fixed by RP2040 code)
+    wait 0 pin 0        ; Stall until start bit is asserted
+
+bitloop:
+   ; Delay until 1/2 way into the bit time
+    mov y, osr
+wait_half:
+    jmp y-- wait_half
+
+    ; Read in the bit
+    in pins, 1          ; Shift data bit into ISR
+    jmp x-- bitloop     ; Loop all bits
+    
+    push                ; Stuff it and wait for next start
+
+
+% c-sdk {
+static inline void pio_rx_program_init(PIO pio, uint sm, uint offset, uint pin) {
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, false);
+    pio_gpio_init(pio, pin);
+    gpio_pull_up(pin);
+
+    pio_sm_config c = pio_rx_program_get_default_config(offset);
+    sm_config_set_in_pins(&c, pin); // for WAIT, IN
+    sm_config_set_jmp_pin(&c, pin); // for JMP
+    // Shift to right, autopull disabled
+    sm_config_set_in_shift(&c, true, false, 32);
+
+    pio_sm_init(pio, sm, offset, &c);
+}
+
+%}

cores/rp2040/pio_uart.pio.h

@@ -0,0 +1,107 @@
+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------ //
+// pio_tx //
+// ------ //
+
+#define pio_tx_wrap_target 0
+#define pio_tx_wrap 5
+
+static const uint16_t pio_tx_program_instructions[] = {
+    //     .wrap_target
+    0xe029, //  0: set    x, 9
+    0x98a0, //  1: pull   block           side 1
+    0x6001, //  2: out    pins, 1
+    0xa046, //  3: mov    y, isr
+    0x0084, //  4: jmp    y--, 4
+    0x0042, //  5: jmp    x--, 2
+    //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program pio_tx_program = {
+    .instructions = pio_tx_program_instructions,
+    .length = 6,
+    .origin = -1,
+};
+
+static inline pio_sm_config pio_tx_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + pio_tx_wrap_target, offset + pio_tx_wrap);
+    sm_config_set_sideset(&c, 2, true, false);
+    return c;
+}
+
+static inline void pio_tx_program_init(PIO pio, uint sm, uint offset, uint pin_tx) {
+    // Tell PIO to initially drive output-high on the selected pin, then map PIO
+    // onto that pin with the IO muxes.
+    pio_sm_set_pins_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_sm_set_pindirs_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_gpio_init(pio, pin_tx);
+    pio_sm_config c = pio_tx_program_get_default_config(offset);
+    // OUT shifts to right, no autopull
+    sm_config_set_out_shift(&c, true, false, 32);
+    // We are mapping both OUT and side-set to the same pin, because sometimes
+    // we need to assert user data onto the pin (with OUT) and sometimes
+    // assert constant values (start/stop bit)
+    sm_config_set_out_pins(&c, pin_tx, 1);
+    sm_config_set_sideset_pins(&c, pin_tx);
+    // We only need TX, so get an 8-deep FIFO!
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    pio_sm_init(pio, sm, offset, &c);
+}
+
+#endif
+
+// ------ //
+// pio_rx //
+// ------ //
+
+#define pio_rx_wrap_target 0
+#define pio_rx_wrap 6
+
+static const uint16_t pio_rx_program_instructions[] = {
+    //     .wrap_target
+    0xe032, //  0: set    x, 18
+    0x2020, //  1: wait   0 pin, 0
+    0xa047, //  2: mov    y, osr
+    0x0083, //  3: jmp    y--, 3
+    0x4001, //  4: in     pins, 1
+    0x0042, //  5: jmp    x--, 2
+    0x8020, //  6: push   block
+    //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program pio_rx_program = {
+    .instructions = pio_rx_program_instructions,
+    .length = 7,
+    .origin = -1,
+};
+
+static inline pio_sm_config pio_rx_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + pio_rx_wrap_target, offset + pio_rx_wrap);
+    return c;
+}
+
+static inline void pio_rx_program_init(PIO pio, uint sm, uint offset, uint pin) {
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, false);
+    pio_gpio_init(pio, pin);
+    gpio_pull_up(pin);
+    pio_sm_config c = pio_rx_program_get_default_config(offset);
+    sm_config_set_in_pins(&c, pin); // for WAIT, IN
+    sm_config_set_jmp_pin(&c, pin); // for JMP
+    // Shift to right, autopull disabled
+    sm_config_set_in_shift(&c, true, false, 32);
+    pio_sm_init(pio, sm, offset, &c);
+}
+
+#endif
+

docs/index.rst

@@ -29,6 +29,7 @@ For the latest version, always check https://github.com/earlephilhower/arduino-p
    EEPROM <eeprom>
    I2S Audio <i2s>
    Serial USB and UARTs <serial>
+   "Software Serial" PIO UART <piouart>
    Servo <servo>
    SPI <spi>
    Wire(I2C) <wire>

docs/piouart.rst

@@ -0,0 +1,22 @@
+"SoftwareSerial" PIO-based UART
+================================
+
+Equivalent to the Arduino SoftwareSerial library, an emulated UART using
+one or two PIO state machines is included in the Arduino-Pico core.  This
+allows for up to 8 additional serial ports to be run from the RP2040 without
+requiring additional CPU resources.
+
+Instantiate a ``SerialPIO(txpin, rxpin)`` object in your sketch and then
+use it the same as any other serial port.  Even, odd, and no parity modes
+are supported, as well as data sizes from 5- to 8-bits.
+
+To instantiate only a serial transmit or receive unit, pass in
+``SerialPIO::NOPIN`` as the ``txpin`` or ``rxpin``.
+
+For example, to make a transmit-only port on GP16
+.. code:: cpp
+
+        SerialPIO transmitter( 16, SerialPIO::NOPIN );
+
+For detailed information about the Serial ports, see the
+Arduino `Serial Reference <https://www.arduino.cc/reference/en/language/functions/communication/serial/>`_ .

keywords.txt

@@ -33,3 +33,4 @@ resumeOtherCore	KEYWORD2
 
 PIOProgram	KEYWORD2
 prepare	KEYWORD2
+SerialPIO	KEYWORD2

libraries/SPI/SPI.cpp

@@ -179,23 +179,22 @@ void SPIClassRP2040::transfer(void *txbuf, void *rxbuf, size_t count) {
 
 void SPIClassRP2040::beginTransaction(SPISettings settings) {
     DEBUGSPI("SPI::beginTransaction(clk=%d, bo=%s\n", _spis.getClockFreq(), (_spis.getBitOrder() == MSBFIRST) ? "MSB" : "LSB");
-    _spis = settings;
-    if (_initted) {
-        DEBUGSPI("SPI: deinitting currently active SPI\n");
-        spi_deinit(_spi);
+    if (_initted && settings == _spis) {
+        DEBUGSPI("SPI: Reusing existing initted SPI\n");
+    } else {
+        _spis = settings;
+        if (_initted) {
+            DEBUGSPI("SPI: deinitting currently active SPI\n");
+            spi_deinit(_spi);
+        }
+        DEBUGSPI("SPI: initting SPI\n");
+        spi_init(_spi, _spis.getClockFreq());
+        _initted = true;
     }
-    DEBUGSPI("SPI: initting SPI\n");
-    spi_init(_spi, _spis.getClockFreq());
-    _initted = true;
 }
 
 void SPIClassRP2040::endTransaction(void) {
     DEBUGSPI("SPI::endTransaction()\n");
-    if (_initted) {
-        DEBUGSPI("SPI: deinitting currently active SPI\n");
-        spi_deinit(_spi);
-    }
-    _initted = false;
 }
 
 bool SPIClassRP2040::setRX(pin_size_t pin) {
@@ -281,6 +280,11 @@ void SPIClassRP2040::begin(bool hwCS) {
 
 void SPIClassRP2040::end() {
     DEBUGSPI("SPI::end()\n");
+    if (_initted) {
+        DEBUGSPI("SPI: deinitting currently active SPI\n");
+        _initted = false;
+        spi_deinit(_spi);
+    }
     gpio_set_function(_RX, GPIO_FUNC_SIO);
     if (_hwCS) {
         gpio_set_function(_CS, GPIO_FUNC_SIO);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "framework-arduinopico",
-  "version": "1.10909.0",
+  "version": "1.10912.0",
   "description": "Arduino Wiring-based Framework (RPi Pico RP2040)",
   "keywords": [
     "framework",

tools/makeboards.py

@@ -162,6 +162,7 @@ MakeBoard("adafruit_qtpy", "Adafruit", "QT Py RP2040", "0x239a", "0x80f7", 250,
 MakeBoard("adafruit_stemmafriend", "Adafruit", "STEMMA Friend RP2040", "0x239a", "0x80e3", 250, "ADAFRUIT_STEMMAFRIEND_RP2040", 8, "boot2_w25q080_2_padded_checksum")
 MakeBoard("adafruit_trinkeyrp2040qt", "Adafruit", "Trinkey RP2040 QT", "0x239a", "0x8109", 250, "ADAFRUIT_TRINKEYQT_RP2040", 8, "boot2_w25q080_2_padded_checksum")
 MakeBoard("adafruit_macropad2040", "Adafruit", "MacroPad RP2040", "0x239a", "0x8107", 250, "ADAFRUIT_MACROPAD_RP2040", 8, "boot2_w25q080_2_padded_checksum")
+MakeBoard("adafruit_kb2040", "Adafruit", "KB2040", "0x239a", "0x8105", 250, "ADAFRUIT_KB2040_RP2040", 8, "boot2_w25q080_2_padded_checksum")
 MakeBoard("arduino_nano_connect", "Arduino", "Nano RP2040 Connect", "0x2341", "0x0058", 250, "ARDUINO_NANO_RP2040_CONNECT", 16, "boot2_w25q080_2_padded_checksum")
 MakeBoard("cytron_maker_nano_rp2040", "Cytron", "Maker Nano RP2040", "0x2e8a", "0x100f", 250, "CYTRON_MAKER_NANO_RP2040", 2, "boot2_w25q080_2_padded_checksum")
 MakeBoard("cytron_maker_pi_rp2040", "Cytron", "Maker Pi RP2040", "0x2e8a", "0x1000", 250, "CYTRON_MAKER_PI_RP2040", 2, "boot2_w25q080_2_padded_checksum")

tools/platformio-build.py

@@ -142,7 +142,8 @@ def configure_usb_flags(cpp_defines):
         ("USB_PID", usb_pid),
         ("USB_MANUFACTURER", '\\"%s\\"' % usb_manufacturer),
         ("USB_PRODUCT", '\\"%s\\"' % usb_product),
-        ("SERIALUSB_PID", usb_pid)
+        ("SERIALUSB_PID", usb_pid),
+        ("USBD_MAX_POWER_MA", 250)
     ])
 
     # use vidtouse and pidtouse 

variants/adafruit_kb2040/pins_arduino.h

@@ -0,0 +1,42 @@
+#pragma once
+
+// Pin definitions taken from:
+//    https://learn.adafruit.com/assets/100337
+
+// LEDs not pinned out
+#define PIN_LED        (31u)
+
+// Serial
+#define PIN_SERIAL1_TX (0u)
+#define PIN_SERIAL1_RX (1u)
+
+// Not pinned out
+#define PIN_SERIAL2_TX (31u)
+#define PIN_SERIAL2_RX (31u)
+
+// SPI
+#define PIN_SPI0_MISO  (20u)
+#define PIN_SPI0_MOSI  (19u)
+#define PIN_SPI0_SCK   (18u)
+#define PIN_SPI0_SS    (31u) // not pinned out
+
+// Not pinned out
+#define PIN_SPI1_MISO  (31u)
+#define PIN_SPI1_MOSI  (31u)
+#define PIN_SPI1_SCK   (31u)
+#define PIN_SPI1_SS    (31u)
+
+// Wire is on the STEMMA QT port
+#define PIN_WIRE0_SDA  (12u)
+#define PIN_WIRE0_SCL  (13u)
+
+// Wire1 is on the breakout pins
+#define PIN_WIRE1_SDA  (2u)
+#define PIN_WIRE1_SCL  (3u)
+
+#define SERIAL_HOWMANY (1u)
+#define SPI_HOWMANY    (1u)
+#define WIRE_HOWMANY   (2u)
+
+#define PIN_NEOPIXEL   (17u)
+#include "../generic/common.h"

variants/adafruit_qtpy/pins_arduino.h

@@ -38,4 +38,10 @@
 #define SPI_HOWMANY    (1u)
 #define WIRE_HOWMANY   (2u)
 
+// Pin overrides specific to the QT Py RP2040
+#define __PIN_A0 (29u)
+#define __PIN_A1 (28u)
+#define __PIN_A2 (27u)
+#define __PIN_A3 (26u)
+
 #include "../generic/common.h"

variants/arduino_nano_connect/pins_arduino.h

@@ -56,19 +56,19 @@ static const uint8_t A5 = (13u);
 #define PIN_SPI0_MISO  (D12)
 #define PIN_SPI0_MOSI  (D11)
 #define PIN_SPI0_SCK   (D13)
-#define PIN_SPI0_SS    (13u)//(D10)
+#define PIN_SPI0_SS    (D10)
 
 #define PIN_SPI1_MISO  (D25)
 #define PIN_SPI1_MOSI  (D28)
 #define PIN_SPI1_SCK   (D29)
-#define PIN_SPI1_SS    (13u)
+#define PIN_SPI1_SS    (D10)
 
 // Wire
 #define PIN_WIRE0_SDA  (D18)
 #define PIN_WIRE0_SCL  (D19)
 
-#define PIN_WIRE1_SDA  (26u) //Non c'è
-#define PIN_WIRE1_SCL  (27u) //Non c'è
+#define PIN_WIRE1_SDA  (D14)
+#define PIN_WIRE1_SCL  (D15)
 
 #define SERIAL_HOWMANY (3u)
 #define SPI_HOWMANY    (2u)
@@ -95,7 +95,7 @@ static const uint8_t SCK = PIN_SPI0_SCK;
 #define SerialHCI		Serial2
 
 //#define NINA_GPIOIRQ	(21u) // LEDG pin (GPIO26 on NINA)
-#define NINA_GPIO0		(20u) // real GPIO0 on NINA
+#define NINA_GPIO0		(D20)   // (2u), real GPIO0 on NINA
 
 #define SPIWIFI_SS		(D26)
 #define SPIWIFI_ACK		(D27)

variants/generic/common.h

@@ -39,12 +39,34 @@ static const uint8_t D27 = (27u);
 static const uint8_t D28 = (28u);
 static const uint8_t D29 = (29u);
 
-static const uint8_t A0 = (26u);
-static const uint8_t A1 = (27u);
-static const uint8_t A2 = (28u);
-static const uint8_t A3 = (29u);
+#ifdef __PIN_A0
+	static const uint8_t A0 = __PIN_A0;
+#else
+	static const uint8_t A0 = (26u);
+#endif
+
+#ifdef __PIN_A1
+	static const uint8_t A1 = __PIN_A1;
+#else
+	static const uint8_t A1 = (27u);
+#endif
+
+#ifdef __PIN_A2
+	static const uint8_t A2 = __PIN_A2;
+#else
+	static const uint8_t A2 = (28u);
+#endif
+
+#ifdef __PIN_A3
+	static const uint8_t A3 = __PIN_A3;
+#else
+	static const uint8_t A3 = (29u);
+#endif
 
 static const uint8_t SS = PIN_SPI0_SS;
 static const uint8_t MOSI = PIN_SPI0_MOSI;
 static const uint8_t MISO = PIN_SPI0_MISO;
 static const uint8_t SCK = PIN_SPI0_SCK;
+
+static const uint8_t SDA = PIN_WIRE0_SDA;
+static const uint8_t SCL = PIN_WIRE0_SCL;