RE: Custom GPIOs and PPI

Charlie — Mon, 21 Feb 2022 13:53:02 GMT

Hi Gavin,

Good to hear that you found the issue. For your question three, I assume you want something like this:

arduino - How do I hook up an LED across the tx pin on my Atmega328? - Electrical Engineering Stack Exchange

If it is true, a hardware circuit is a better solution like the above case than monitoring with PPI, but this is not very common for SPI bus, since its speed starts with tens Mbps. You can barely see anything since its too fast for your eyes.

Best regards,

Charlie

RE: Custom GPIOs and PPI

Gavin — Sat, 19 Feb 2022 18:57:42 GMT

I have just realised that pin P0.09 is associated with NFC connector. I have changed the code to reference pin P0.11 and it is now working.

However I am still interested in the answer to question 3:

3/ once I have solved this basic problem, I might want to use the LEDs to indicate the status of the MOSI and MISO lines on the SPI interface. Is it possible to use PPI to monitor the status of a pin that is being used by the SPI peripheral in this way? If so, how would I adapt the code or .overlay file to associated one of the SPI pins with the PPI input?