* Convert to SDK RP2350A/B determination
Fixes#2878
The SDK uses `defined(PICO_RP2350) && !PICO_RP2350A` to indicate an RP2350B
chip, not the define PICO_RP2350B.
Match the SDK's usage by converting from `defined(PICO_RP2350B)` to
`defined(PICO_RP2350) && !PICO_RP2350A` and update the chip variants
accordingly.
* Need to explicitly override PICO_RP2350A for all
The *SDK*'s board definition file hardcodes a PICO_RP2350A value for
all boards, but we use the same board file for both A and B variants.
Override the SDK board definition in the variant definition file.
* Generic RP2350 needs 2-stage PICO_RP2350A setting
Also ensure SDK board definition included before pins_arduino.h for
clearing up redefinition errors.
* Factor out undef PICO_RP2350A
* Update Arduino.h
When multiple inputs were active, the frequency was being scaled two
times resulting in incorrect sampling speed. Correct to only scale
the calculation and not the stored value (which is used in `begin`).
Fixes#2754
Mimics the I2S/PWMAudio/Stream interface for ease of use.
* Fix non-32b DMA size transfer calculation in ABM
* Rename wasHolding to isHolding in the I2S/PWM
It is the **current** number of bits left, not the past number.
* Add commented microphone example
* Add docs
Earle F. Philhower, III