[nRF24L01+] How to use Auto Acknowledge

[_pascalh]

Hello all,

1. I have a transmitter (Arduino Pro Mini 5V) connected to a nRF24L01+. I use the following code to set up the radio.

    radio.begin();
    radio.setChannel(125);
    radio.setPALevel(RF24_PA_LOW);
    radio.setDataRate(RF24_1MBPS);
    radio.setAddressWidth(5);
    radio.setAutoAck(true);
    radio.setRetries(5, 3);
    radio.setPayloadSize(sizeof(radio_data));
    radio.openWritingPipe(address);
    radio.stopListening();

2. I have a receiver (ESP32) coonecter to a nRF24L01+. I use the following code to set up the radio.

    radio.begin();
    radio.setChannel(125);
    radio.setPALevel(RF24_PA_LOW);
    radio.setDataRate(RF24_1MBPS);
    radio.setAddressWidth(5);
    radio.setAutoAck(true);
    radio.setRetries(5, 3);
    radio.setPayloadSize(sizeof(radio_data));
    radio.openReadingPipe(0, address);
    radio.startListening();

3. When I want to transmit data, I call the function write.

The return of the call to the function write is always false, meaning that auto acknowledgement goes wrong.

Have you any idea of what I did wrong ?

Thanks for your help.

[ovrebekk]

Hi 

Is anything received by the ESP32 board?

The nRF24L01+ is rated to 3.6V maximum, so I think the first order of business would be to test this on boards that support a lower supply voltage. Correct behavior can not be guaranteed when you're running the nRF device at 5V, and it might damage the module over time. 

Best regards
Torbjørn

[_pascalh]

Hello,

First, the nRF24L01+ is not supplied with the 5V of transmitter Arduino, but with 3.3V.

Second, with the channel set to 125, the receiver ESP32 is not receiving at all. If I remove the call to setChannel, the ESP32 is receiving around 20% of the frame and in that case, the Arduino is getting the ACK.
So, 80% of frame are lost with no ACK.

As an information, there is a 10µF capacitor at the pin GND/3.3V of the receiver nRF24L01+ and a 100µF capacitor for the transmitter nRF24L01+.

Best regards.

[_pascalh]

Hello,

I put a link to the sal file from Saleae logic analyzer which captures SPI during more than 2 seconds. 2 frames have been ACKed (the 2nd one and the 15th one). All others, no ACK.

I used the function printPrettyDetails of the Arduino library to get information about configuration of radio. Here after are the results. Let me know if you need more.

SPI Frequency = 1 Mhz
Channel = 76 (~ 2476 MHz)
Model = nRF24L01+
RF Data Rate = 1 MBPS
RF Power Amplifier = PA_MIN
RF Low Noise Amplifier = Enabled
CRC Length = 16 bits
Address Length = 5 bytes
Static Payload Length = 20 bytes
Auto Retry Delay = 1500 microseconds
Auto Retry Attempts = 15 maximum
Packets lost on
current channel = 0
Retry attempts made for
last transmission = 15
Multicast = Disabled
Custom ACK Payload = Disabled
Dynamic Payloads = Disabled
Auto Acknowledgment = Enabled
Primary Mode = TX
TX address = 0x3145504950
pipe 0 ( open ) bound = 0x3145504950
pipe 1 ( open ) bound = 0xc2c2c2c2c2
pipe 2 (closed) bound = 0xc3
pipe 3 (closed) bound = 0xc4
pipe 4 (closed) bound = 0xc5
pipe 5 (closed) bound = 0xc6

My feeling is that the transmitter works fine, but the problem is more on the ESP32 receiver.

Best regards.

https://drive.google.com/file/d/1JlGj0eRhPx7e-lvl3_OzgsQCcF71NEYF/view?usp=drive_link

[ovrebekk]

Hi 

Thanks, I will take a look at the traces tomorrow. 

Does the trace show the entire startup sequence, including all the register configuration commands? 

This would be helpful to make sure I have the full picture. 

Best regards
Torbjørn

[_pascalh]

Hi,

The trace has been done during the running mode.
Here after is the link to access the trace done from the start.

https://drive.google.com/file/d/1Dy7Wsl3x0wbE_84zWVPLHm7X22tyhh4X/view?usp=drive_link

Best regards.

[ovrebekk]

Hi 

Did you get my request for access to the file? 

You need to approve it before I can open it. 

Best regards
Torbjørn

[_pascalh]

Hello,

I just accept your request.

Best regards.

[ovrebekk]

Hi 

Thanks, I was now able to access the file. 

I can't really see any obvious issues with the code, but if you can share the corresponding trace for the PRX also that would be interesting. 

If you can, please include the IRQ  and CE lines in the trace as well. 

One odd thing is that there seems to be two configuration phases, about 5ms apart, but possibly this is just how the library is designed. 

If the PRX trace doesn't show anything interesting either I will try to hook up some nRF24L01+ modules here and see if I can reproduce the issue. 

Best regards
Torbjørn

[_pascalh]

Hello,

I've added 2 trace files in my drive for which I granted you access with a message. One for the TX with the CE from the start, one for the RX with the CE from the start.

Could you also provide me with some manufacturers.

I found the manufacturer Wellman and the product WPI322. Is it worth to buy 2 devices?

Best regards,

Pascal

[ovrebekk]

Hi Pascal

Do you have a link to the WPI322 module? 

Sparkfun made a module called WRL-00691 which can be had from mouser (and maybe others), and there is also the official Nordic module which can be found some places (such as here). 

I was able to download your traces. I need some more time to look into it, but will do my best to provide an update by the end of the week. 

Best regards
Torbjørn

[_pascalh]

Hello,

I bought the official Nordic module (NRF24L01P-MODULE-PCB).

I got the same result : no ACK received by the transmitter from the receiver, and receiver losing frames.

Best regards,

Pascal

[ovrebekk]

Hi Pascal

Do you have the capability to send raw SPI commands to the module, bypassing the L01+ library? 

It should be possible to enable the module and send packets with ACK using only a handful of SPI commands. If you are able to bypass the library and control the SPI and GPIO directly I can suggest a short test sequence that can verify that the hardware is OK. Then we have to figure out what is different when using the library, and (ideally) how to make the library work correctly. 

Best regards
Torbjørn