PIO SPI Example not working for GPIO>=32

[viralpatel9]

I am trying to run PIO SPI example using GPIOs more than 31, but I am not able to initialise them correctly. Things I have configured in my SDK:

• I have changed the #define PICO_RP2350A 0
• I have added gpio base to 16 for my pio1 using pio_set_gpio_base(pio1, 16);

I am using the latest SDK v2.2.0

[peterharperuk]

What gpios are you using? Are you using a board based on rp2350? What do you mean by "not able to initialise them correctly"?

[viralpatel9]

Yes, I am using RP2350B variant and I am trying to configure my SPI using below GPIOs

{43, 46, 45},  // SCK, MOSI, MISO

I am toggling the CS pin (GPIO44) using generic GPIO APIs, which seems to work ok, but I can't see any behaviour on any of the other GPIOs (on scope).

I am using https://github.com/raspberrypi/pico-examples/blob/master/pio/spi/spi.pio example where my cpol=0 and cpha=1

[peterharperuk]

Yes, I am using RP2350B

Make sure you are using a PICO_BOARD that has PICO_PIO_VERSION > 1
It doesn't look like pio_spi_init will work for >32 so that will need to be fixed.

[viralpatel9]

I believe this is not the SDK limitations, and I can try and fix the pio_spi_init function to work with RP2350B variant?

[peterharperuk]

Yes, its the example that needs to be fixed.

[viralpatel9]

Hi, I have created a minimal code here https://github.com/viralpatel9/test-pio?tab=readme-ov-file#issue-with-pins32-on-rp2350b to report this issue. I have tried different combinations (of GPIOs) with my SPI peripheral (INA229) that I have been using. Unfortunately, I haven't got it working. Would you mind reviewing the code and seeing if I have missed anything? Thanks.

[peterharperuk]

Your code looks ok. Are you sure you have the pins connected correctly?
The only issue is with the line...

hw_set_bits(&pio->input_sync_bypass, 1u << pin_miso);

which should be changed to something like...

hw_set_bits(&pio->input_sync_bypass, (pin_miso >= 32) ? (1u << (pin_miso - 16)) : (1u << pin_miso));

But I wouldn't expect that to be an issue here.
I also don't understand this comment...

/* This configuration should not work but it does */

I don't have an ina229 or else I'd try testing with that.

[viralpatel9]

Hi @peterharperuk, it appears to be working now. The issue was on the hardware side (INAs); they were not getting powered correctly. I have created a PR just in case. Please feel free to close this issue if needed. Thanks for your support.