nRFL24LE1, 250Kbps not working

[mr_creosote]

Hi, I'm new to Nordic. I can't get 250Kbps working on the nRF24LE1. I'm using the enhanced shockburst examples in the nRFgo SDK (enhanced_shockburst_ptx_nrf2 and enhanced_shockburst_prx_nrf2). I added a call to hal_nrf_set_datarate:

// Power up radio

hal_nrf_set_power_mode(HAL_NRF_PWR_UP); hal_nrf_set_datarate(HAL_NRF_250KBPS);

//HAL_NRF_1MBPS, /**< Datarate set to 1 Mbps */

//HAL_NRF_2MBPS, /**< Datarate set to 2 Mbps */

It works fine if I change it to 2Mbps and 1Mbps. I'm changing the data rate at both the transmitter and the receiver, of course. What am I doing wrong?

I posted this question on the devzone (https://devzone.nordicsemi.com/question/106546/nrf24le1-250kbps-not-working/) but as I haven't gotten answers to any of my previous questions, I'm asking the same question here.

Thanks!

Mahesh

[Håkon Alseth]

Hi Mahesh,

 

I suspect the 250 kBit mode does not work due to the auto-retransmit delay.

For 250k, this should be set to 500 us or higher, depending on how much data is sent back in the ACK-payload (see page 29 in the datasheet, chapter 3.4.6.2, for more detailed information). 

 

Could you try altering the "ARD" using API call hal_nrf_set_auto_retr(retr, delay), where delay is the parameter that you should set to atleast 500 us.

 

Best regards,

Håkon