RF link with nRF24L01+ receiver not responding

RE: RF link with nRF24L01+ receiver not responding

Kurtlin — Thu, 23 Apr 2026 22:09:25 GMT

Hi Ressa,

I copied the code from:

Problem with nrf24l01 ACK Comunication, can't make it to work"

and it worked. I have not worked out why, but I think it has to do with the

RX_PW_PX registers and the EN_RXADDR registers.

Anyway, it works now, thanks very much for your help

Best regards

Kurt

RE: RF link with nRF24L01+ receiver not responding

Ressa — Wed, 22 Apr 2026 11:27:17 GMT

Hi Kurt,

Could you please check below ticket as it describes minimal settings for bidirectional operation:
(+) Problem with nrf24l01 ACK Comunication, can't make it to work - Nordic Q&A - Nordic DevZone - Nordic DevZone

By checking that , just wondering if the 2ms delay is applied after powering up the RX/TX and before setting CE high ?

Best regards,
Ressa

RE: RF link with nRF24L01+ receiver not responding

Kurtlin — Fri, 17 Apr 2026 00:47:08 GMT

Hi Ressa,

I changed the RF setup (Reg 0x06) to 0x26 (256kBs)

after the 2 flush commands

I sent Reg 0x07 -> 0x70

then reg 0x00 ->3A

On the transceiver I send then the 2 bytes every 1sec

CE->L
reg 0x00 -> 3A
Flush TX
Write 0xA0, Byte 1, Byte 2
CE->H
15us wait
CE->L
reg 0x00 -> 3B
CE->H

on the receiver

reg 0x00 ->3B
CE->H

loop INT = L ?

still no response!!??

best regards

Kurt

RE: RF link with nRF24L01+ receiver not responding

Ressa — Mon, 13 Apr 2026 14:10:01 GMT

Hi Kurt,

Did you try with 1 Mbps rate as well ? Did it make any difference ? Also please try to clear IRQ flag at least on RX side , right after flushing the TX/TX settings:

Also there should be some delays in applying the settings. After power up (0x00 - 0x3A/0x3B ), it needs 1.5 ms before radio is ready. So after power up make sure to add this delay . Also after setting CE high, on RX side, it start receiving packets after 130 us. Make sure the TX and RX are following these timing.

devzone.nordicsemi.com/.../nRF24L01P_5F00_PS_5F00_v1.0.pdf

There is an old page that contains all SW/HW files with few SW samples for nRF24L01+ in below link:
nRF24 Series - Nordic Semiconductor - nordicsemi.com

Also please have a look at below ticket which might be similar problem here. Not emptying RX FIFO might be the issue as it prevents receiving new packets:

Nordic DevZone

Let me know if none of the suggestions solve the issue.

Best regards,
Ressa

RE: RF link with nRF24L01+ receiver not responding

Kurtlin — Fri, 10 Apr 2026 04:50:23 GMT

Hi Ressa,

I checked the code again; sorry I made a mistake when I wrote the register setup in my first message. it's definitely 2, I checked by reading back.

I don't have a circuit with antenna connection, I use a module with 8pins and a PCB antenna.

modules are only max 0.5m - 1.0 m apart.

Best regards

Kurt

RE: RF link with nRF24L01+ receiver not responding

Ressa — Wed, 08 Apr 2026 12:46:12 GMT

Hi Kurt,

Thanks for the information. IRQ pin (from nRF24L01+ side) is a digital output pin and it will gives a pulse if any reception occurs. It would have been great if you could provide full schematic of nRF24L01+ , I mean ANT pin as well. You can change the ticket from public to private for sharing.

Just one small mismatch, the payload length you are setting is 3 bytes : 0x11 0x03 , but actually sending two bytes: write 0xA0, Byte1, Byte2 . Is it the case ?
I would also suggest to first try with 1 Mbps data rate instead of 2Mbps.

Best regards,
Ressa

RE: RF link with nRF24L01+ receiver not responding

Kurtlin — Tue, 31 Mar 2026 00:10:36 GMT

Hi,

CE pin is pulled H after flush RX/TX and setting register 0x00->0x3A (checked with multimeter)

I also read the register content back out, it's the same!

here is the circuit

IRQ is input with pull up resistor, stays always H

Best regards

Kurt

RE: RF link with nRF24L01+ receiver not responding

Ressa — Mon, 30 Mar 2026 15:09:43 GMT

Hi,

I just looked into available materials for nRF24L01+ and the settings seems to be ok. Just wondering how is the status of CE pin during the operation? Also you don't receive any signal on IRQ pin either?
Could you please share schematic of the design mainly the section relevant to nRF24L01+ ?