RP2 SPI: Instantiating with spi=None does not behave sensibly.
The constructor accepts None as an arg to miso, but still instantiates the default pin.
The clear intent is to create an output-only interface. Either it should reject the arg or (preferably) it should not instantiate a pin. Current behaviour can lead to unexpected pin conflicts.
This should also apply to mosi.
When miso=None is set, the default miso pin changed state.
Port, board and/or hardware
Raspberry Pi Pico W
MicroPython version
MicroPython v1.24.1 on 2024-11-29; Raspberry Pi Pico W with RP2040
Reproduction
RS = Pin(16, Pin.OUT)
spi = SPI(0,
baudrate=400000,
polarity=0,
phase=0,
bits=8,
firstbit=SPI.MSB,
sck=Pin(18),
mosi=Pin(19),
miso=None)
RS.value(0)
time.sleep_ms(1)
RS.value(1)
Expected behaviour
Expected to set up SPI without MISO, set the RS pin value to 0, and after 1 ms, set the RS pin value to 1.
Observed behaviour
The SPI was set up correctly, but the RS pin's value never changed.
Additional Information
If I set up the pin after initializing SPI, it works as expected, the used pin 16 is default pin for miso. I think this bug is on other types of RPIs Pico.
Code of Conduct
Yes, I agree