This commit adds I2S protocol support for the rp2 port:
- I2S API is consistent with STM32 and ESP32 ports
- I2S configurations supported:
- master transmit and master receive
- 16-bit and 32-bit sample sizes
- mono and stereo formats
- sampling frequency
- 3 modes of operation:
- blocking
- non-blocking with callback
- uasyncio
- internal ring buffer size can be tuned
- DMA IRQs are managed on an I2S object basis, allowing other
RP2 entities to use DMA IRQs when I2S is not being used
- MicroPython documentation
- tested on Raspberry Pi Pico development board
- build metric changes for this commit: text(+4552), data(0), bss(+8)
Signed-off-by: Mike Teachman <mike.teachman@gmail.com>
