RE: Issue seen with nRF52840 and SPI (Master) Receving Bytes

Jay — Sat, 17 Jun 2017 21:11:21 GMT

Ah, that makes sense! Thank you for your answer. I am currently using the SDK 13 and the issue I described (which is not an issue after reading your answer) makes sense since the the MISO pin is set to pulldown. So, when I send via MOSI, I will always get 0x00 (i.e., making it look like first RX byte is 'ignored').

RE: Issue seen with nRF52840 and SPI (Master) Receving Bytes

Jørgen Holmefjord — Wed, 14 Jun 2017 09:27:22 GMT

Hi Jay,

SPI protocol is full duplex, meaning it can transmitt and receive at the same time. You should not see (# TX + # RX) cycles, but MAX(# TX, # RX) cycles. Since you tell the driver you want to receive 4 bytes, you will see 4 cycles. The first cycle will be both transmitt and receive cycle.

I'm not able to reproduce the other issue you describe, using you code and the SPI example in SDK 13.0.0. Which example and SDK version are you using?

Best regards,

Jørgen