nrf52840 as SPI slave not receiving data

[AjayH]

Hi.

I am trying to use nrf52840 on a custom board and configure it as spi slave, and an STM32H7 controller would be the master. I am using the spis example for nrf. I have cross verified all pin configurations and set it correctly, and set same clock polarity and phase on both controllers, also the controllers are at common ground.

I am able to receive spi data for the same configuration using nrf52840-dk and an STM nucleo board, but not able to receive any data on the custom board.

When debugged on the custom board, the code is always stuck in !spis_xfer_done loop. For the sake of testing, I have commented the LOG sections. 

Also, using an oscilloscope on the custom board, I can see the STM32 controller is transmitting the test data. 

The waveform is captured at the STM transmission end on the custom board.

Have I missed something? Any guidance would be helpful.

Thanks,

Ajay

[Simon]

Have you checked the logic value of CSN (chip select) throughout the transmission? Could you check if any other peripherals are using any of the SPIS pins?

Have you checked out these cases?

• https://devzone.nordicsemi.com/f/nordic-q-a/23005/programming-nrf52840-on-custom-board
• https://devzone.nordicsemi.com/f/nordic-q-a/39670/can-t-read-or-write-spis-data-on-nrf52-gpio
• https://devzone.nordicsemi.com/f/nordic-q-a/18173/spis-endrx-event-not-working

Best regards,

Simon

[AjayH]

Hi Simon,

The CS was the issue at the STM end, as it wasn't configured properly. However, the same case was in the dk but I was receiving correct values then. So I just assumed configurations are fine and checked for the data transmission. Now I have configured the STM controller properly, and able to receive data on the custom board.

Thanks for the support.