For compatibility with other ports. Code increase up to ~1250 bytes for
SAMD21. The feature is configurable via MICROPY_PY_MACHINE_PIN_BOARD_CPU
in case flash memory is tight.
Pin numbers are now the MCU port numbers in the range:
PA0..PA31: 0..31
PB0..PB31: 32..63
PC0..PC31: 64..95
PD0..PD31: 96..127
Pins can be denoted by the GPIO port number, the name as defined in
pins.csv or a string in the form Pxnn, like "PA16" or "PD03".
The pins.c and pins.h files are now obsolete. The pin objects are part of
the AF table.
As result of a simplification, the code now supports using pin names or
numbers instead of pin objects for modules like UART, SPI, PWM, I2C, ADC,
pininfo.
It's no longer needed because this macro is now processed after
preprocessing the source code via cpp (in the qstr extraction stage), which
means unused MP_REGISTER_MODULE's are filtered out by the preprocessor.
Signed-off-by: Damien George <damien@micropython.org>