SPIM - RX buffer is empty but MISO line shows correct traffic on Logic Analyzer

RE: SPIM - RX buffer is empty but MISO line shows correct traffic on Logic Analyzer

hmolesworth — Fri, 07 Feb 2020 15:32:00 GMT

You're welcome. Here are a few recent post I made on the subject, with a little more useful info on using SPI:

nrf52832-get-wrong-who_am_i-value-with-spi

unable-to-interface-nrf51822-with-lis3dh-accelerometer-using-spi-being-nrf-as-master

RE: SPIM - RX buffer is empty but MISO line shows correct traffic on Logic Analyzer

lbe — Fri, 07 Feb 2020 08:25:02 GMT

Thanks a lot, I confirm that the right value is in second position! I tried to look in the forum before posting, but I didn't come to any older post on the subject.....but ok important thing is that everything works as expected now!

RE: SPIM - RX buffer is empty but MISO line shows correct traffic on Logic Analyzer

hmolesworth — Thu, 06 Feb 2020 17:09:42 GMT

The data you seek is not in spi_rx_buff[0] but in spi_rx_buff[1]; the first byte received is a dummy byte clocked in while the command byte is clocked out, the data is in the 2nd received byte. You will also need to change if (spi_rx_buff[0] != 0) to check that 2nd byte. There are quite a few posts explaining why in more detail, but I don't have links to hand.