SPI communication failure between nRF52840 Preview DK and Arduino UNO

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

ovrebekk — Wed, 25 Apr 2018 06:41:12 GMT

Hi Rubens

I am sorry for the slow response, it was hard to find some time to dig into this...

Finally I got my Arduino Uno running, and I am also having some issues getting communication between the two.

What I just realized is that the voltage between the two boards will not be compatible. The Arduino runs at 5V, while the nRF52840 PDK runs at around 3.0V normally, and this is likely to cause issues when you try to establish communication between the two.

I would recommend you either put level shifters on your SPI lines to do the voltage conversion, or hack your Arduino to run at 3.3V as described here.

Best regards
Torbjørn

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

Ree Wang — Wed, 04 Apr 2018 00:11:35 GMT

Hi ovrebekk,

Have you got chance to reproduce this issue?

Best regards

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

Ree Wang — Mon, 19 Mar 2018 22:29:13 GMT

Thanks Turbo,

I have removed the print() from my code, but still the issue is...

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

Turbo J — Sat, 17 Mar 2018 19:02:57 GMT

The Serial.print() calls in the ISR can take waaay longer than the SPI transaction, so you may loose a lot of chars in between. Better to use a FIFO here and print the stuff from main loop().

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

Ree Wang — Sat, 17 Mar 2018 12:38:03 GMT

Thank you very much!

For above code, what I expect is when Nordic DK send any char to Arduino Uno, Nordic DK should receive the same char when Nordic DK transfers next char. In above case, 'N' should be repeatedly send and received by Nordic DK.

In Arduino side, I can see that the log shows 'N' is received properly and set in register for reply. However, in Nordic DK log, I cannot see correct answer.

I have tested different mode, but both them are failed to get correct reply.

Best regards.

RE: SPI communication failure between nRF52840 Preview DK and Arduino UNO

ovrebekk — Wed, 14 Mar 2018 15:11:31 GMT

What is wrong with the response?
Are you able to list what you receive, and what you expected to receive?

If you have the wrong mode configured in one of the boards it's not uncommon for data transaction to only work in one direction.

Could you try changing the mode in the Nordic code and see if it makes a difference?
Try MODE_2 first, and if that doesn't work you can try MODE_1 and MODE_3 as well.

If nothing else works I will try to reproduce your issue on my end, and see if I can spot the issue.

Best regards
Torbjørn