MAX_RT interrupt still happens even if retransmit is off

[harryAI]

Dear Nordic,

I met a problem while using nRF24L01+ about MAX_RT interrupt.

In my codes, I disabled RF HW retransmit (hal_nrf_set_auto_retr(0, RF_RETRANS_DELAY);) because I use our software codes to handle retransmit. Therefore, RF should not report "HAL_NRF_MAX_RT" interrupt. However, I still receive "HAL_NRF_MAX_RT" in very rare situations. I saw twice so far for a very long time.

My question is since RF module auto retransmition is off, why does nRF24L01+ still report "HAL_NRF_MAX_RT" interrupt?? Is this nRF24L01+ bug? Or how could I do to get rid of these
MAX_RT interrupt?

[harryAI]

Yes, I need dynamic payload length.

Therefore, my codes will call

* run hal_nrf_open_pipe(HAL_NRF_PIPE0, true), 

* hal_nrf_setup_dyn_pl(ALL_PIPES)

* hal_nrf_enable_dynamic_pl().

and will NOT call (comment out)

* hal_nrf_enable_ack_pl();

Got it. thank you very much.

[ovrebekk]

Hi 

That sounds good. 

If you have any more problems just let me know

Best regards
Torbjørn

[harryAI]

Hi Torbjorn,

I follow your comments, but RF does not produce any TX_DS interrupt event anymore. The whole system cannot work.

I just copy my codes below (remove all comments to save space). Could you please help to check what's matter.

void radio_pl_init (uint8_t *address, hal_nrf_operation_mode_t operational_mode,
uint8_t rfChannel, hal_nrf_datarate_t airRate)
{
hal_nrf_close_pipe(HAL_NRF_ALL);
hal_nrf_open_pipe(HAL_NRF_PIPE0, true);
hal_nrf_set_crc_mode(HAL_NRF_CRC_16BIT);
hal_nrf_set_auto_retr(0, RF_RETRANS_DELAY);
hal_nrf_set_address_width(HAL_NRF_AW_5BYTES);
hal_nrf_set_address(HAL_NRF_TX, address);
hal_nrf_set_address(HAL_NRF_PIPE0, address);

//hal_nrf_enable_ack_pl(); // Try to enable ack payload

if(hal_nrf_read_reg(FEATURE) == 0x00 && (hal_nrf_read_reg(DYNPD) == 0x00))
{
hal_nrf_lock_unlock (); // Activate features
//hal_nrf_enable_ack_pl(); // Enables payload in ack
}

hal_nrf_enable_dynamic_pl();
hal_nrf_setup_dyn_pl(ALL_PIPES);

if(operational_mode == HAL_NRF_PTX)
{
hal_nrf_set_operation_mode(HAL_NRF_PTX);
}
else
{
hal_nrf_set_operation_mode(HAL_NRF_PRX);

// Disable this. Use dynamic payload, so no need to set the fixed payload length.
//hal_nrf_set_rx_pload_width((uint8_t)HAL_NRF_PIPE0, RF_PAYLOAD_LENGTH);
}

hal_nrf_set_rf_channel(rfChannel);
hal_nrf_set_power_mode(HAL_NRF_PWR_UP);
hal_nrf_set_datarate(airRate);
start_timer(RF_POWER_UP_DELAY);
wait_for_timer();

//radio_set_status (RF_IDLE);
}

[ovrebekk]

Hi 

Are you able to send me the implementation of the hal_nrf_enable_dynamic_pl() function?

In my version of the HAL library this function needs to be provided a bool argument, allowing you to enable or disable the feature. 

I realize now that I forgot to mention that you have to call  hal_nrf_enable_dynamic_ack(true) also if you want to use the noack feature. 

Below is my own test code to verify that this is working: 

hal_nrf_set_operation_mode((config->mode == APP_RADIO_MODE_PTX) ? HAL_NRF_PTX : HAL_NRF_PRX);

hal_nrf_set_power_mode(HAL_NRF_PWR_UP);

nrf_delay_us(1500);

hal_nrf_set_crc_mode(HAL_NRF_CRC_16BIT);

hal_nrf_set_auto_retr(0, 500);

hal_nrf_close_pipe(HAL_NRF_ALL);
hal_nrf_open_pipe(HAL_NRF_PIPE0, true);

hal_nrf_set_address_width(5);

hal_nrf_setup_dynamic_payload(0x3F);
hal_nrf_enable_dynamic_payload(true);
hal_nrf_enable_dynamic_ack(true);

hal_nrf_set_datarate(HAL_NRF_2MBPS);

hal_nrf_set_rf_channel(2);

if(config->mode == APP_RADIO_MODE_PTX)
{
  hal_nrf_flush_tx();
}
else
{
  hal_nrf_flush_rx();
  hal_nrf_set_rx_payload_width(HAL_NRF_PIPE0, 8);
}

And then I send my packets using the hal_nrf_write_tx_payload_noack(..) function, which removes the ACK requirement from the packet.

Best regards
Torbjørn

[harryAI]

> Are you able to send me the implementation of the hal_nrf_enable_dynamic_pl() function?

Here you are.

void hal_nrf_enable_dynamic_pl(void)
{
hal_nrf_write_reg(FEATURE, (hal_nrf_read_reg(FEATURE) | 0x04));
}

void hal_nrf_disable_dynamic_pl(void)
{
hal_nrf_write_reg(FEATURE, (hal_nrf_read_reg(FEATURE) & ~0x04));
}