This commit adds support for machine.I2S on the mimxrt port. The I2S API
is consistent with the existing stm32, esp32, and rp2 implementations.
I2S features:
- controller transmit and controller receive
- 16-bit and 32-bit sample sizes
- mono and stereo formats
- sampling frequencies from 8kHz to 48kHz
- 3 modes of operation:
- blocking
- non-blocking with callback
- uasyncio
- configurable internal buffer
- optional MCK
Tested with the following development boards:
- MIMXRT1010_EVK, MIMXRT1015_EVK, MIMXRT1020_EVK, MIMXRT1050_EVK
- Teensy 4.0, Teensy 4.1
- Olimex RT1010
- Seeed ARCH MIX
Tested with the following I2S hardware peripherals:
- UDA1334
- GY-SPH0645LM4H
- WM8960 codec on board the MIMXRT boards and separate breakout board
- INMP441
- PCM5102
- SGTL5000 on the Teensy audio shield
Signed-off-by: Mike Teachman <mike.teachman@gmail.com>
Using the keyword argument cs=nnn in the constructor. The cs1
pin has to be defined in mpconfigboard.h.
Note: Only a few boards have the CS1 pin exposed to the connectors.
The Pin config setting by IOMUXC_SetPinConfig() is supplied by a
bit pattern. That pattern is specific for a MCU family. In preparation
for supporting the MIMXRT117x family, the constant bit pattern is
replaced by a function call, such that the bit pattern is created
at a single place. The code for this functions was taken from
machine_pin.c.
Note: A working port for the MIMXRT1176 exists already.
This library file has a bug, in that TransferBlocking returns before the
transfer has finished. That is a problem if a write follows immediately
a read.
This class supports SPI bus controller mode, with blocking transfers.
SPI device numbers start at 0, to comply with the pinout of the Teensy
boards. With the configured clock frequency the fastest baud rate is
33MHz. For messages longer 16 bytes DMA is used. The class uses the
existing framework with extmod/machine_spi.c.
Extended driver options:
- drive=n with n being between 1 and 6 or PIN.POWER_1 to PIN.POWER_6.
Since the pins used by the SPI are fixed, no Pin settings can be made.
Thus the drive option is added allowing to control ringing and crosstalk
on the connection.
- gap_ns=nnnnn is the time between sent data items in a frame given in ns.
Default is 2 clock cycles.
