nrf24l01+: ack payload length > 1 on PRX TX'ed => Same data as first byte RX'ed on PTX.

[ApaX]

I have two NRF24L01+ modules - I am not sure if they are fake?

One node acts as PTX and another as PRX.

On both devices i have the features auto_ack and ack_payload enabled.

I can send data between PTX and PRX with no problem.

If i use the PRX ack payload with 1 byte i have no problem in receiving this on PTX. I change the value of the payload with CMD_W_ACK_PAYLOAD command.

if i have a ack payload length > 1 byte, lets say 10 bytes - and change the data with CMD_W_ACK_PAYLOAD on the PRX i get 10 bytes back on PTX.. but all bytes are identical to first byte...

Does this make sense?

Can i read the content of the ack payload on the PRX to verify my data?

[Hung Bui]

@ApaX: I would need to see how you do nrf24_Read_RxPayload

I attached in my answer above an example. It's for the nRF24LE1 but the radio and the register are the same with nRF24L01. You can compile the example using the nRFGo SDK here.

I can see that you are expecting 2 bytes from the ack payload ?

[ApaX]

Thank you for your answer.

Yes i've changed it from 10 bytes to 2. Just for simplicity. My code is working just fine with one ACK-payload-length. But with more than one ack-payload-length, the first ack payload is copied to the entire length.

uint8_t nrf24_Read_RxPayload(uint8_t *pBuff, uint8_t Len)
{
  if (Len > 32)
    Len = 32;
  return nrf24_read(nrf24_SPIx, NRF24_CMD_R_RX_PAYLOAD, pBuff, Len);
}



uint8_t nrf24_read(SPI_TypeDef* SPIx, uint8_t Cmd, uint8_t *pBuff, uint8_t Len)
{
  NRF24_CSN_LOW();


  uint8_t State = SPI_SendRecvByte(SPIx, Cmd);

  SPI_recv8b(SPIx, pBuff, Len);
  
  NRF24_CSN_HIGH();

  return State;
}

General question: Is it possible to have more than one ACK-payload byte sent (as auto response) via. Enhanced ShockBurst?

[Hung Bui]

Yes, it is possible to send more than one byte. You can have a look in the example I attached, there are 3 bytes sending as ACK payload.

[Hung Bui]

@ApaX: could you try to look into the example I provided in the answer above(that should be used with the nRFGo SDK ) and follow what we have there ? Especially the hal_nrf_read_multibyte_reg() function. We actually do a read for hal_nrf_read_rx_payload_width() before we read the buffer.

The nRF24LE1 and the nRF24L01P has the same radio