Can I get some clarification regarding pipes and addresses?

RE: Can I get some clarification regarding pipes and addresses?

JimR — Tue, 08 Aug 2017 00:15:00 GMT

Hi Hung Bui, Thanks for that clarification. I think that does resolve my confusion! JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Mon, 07 Aug 2017 12:44:03 GMT

I know, it's confusing, the variants :) But the nRF2401 is very very very old, must be more than 12 years.

On the nRF24L01P, Enhances Shockburst is enabled by default.

On the nRF24L01, you need to call ACTIVATE to activate ESB (meaning auto ACK)

Of course you have to make sure you don't disable ACK by using dynamic payload (set NO_ACK bit to high).

RE: Can I get some clarification regarding pipes and addresses?

JimR — Sat, 05 Aug 2017 22:21:39 GMT

Hi Hung Bui, I'm using and I was talking about the nRF24L01P, and I simply want to ensure that modules using this chip are compatible with those using the nRF24L01. It looks like I was misreading the info on page 49, because I hadn't noticed that it was talking about backward compatibility with the nRF2401 and so on, NOT the nRF24L01. You have so many variants! Anyway, am I right that this means that I need to enable Enhanced ShockBurst to get my modules exchanging ACKs? JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Fri, 04 Aug 2017 11:21:19 GMT

Please clarify, are you talking about nRF24L01 or nRF2401 ? page 49 was about nRF2401.

RE: Can I get some clarification regarding pipes and addresses?

JimR — Thu, 03 Aug 2017 22:04:40 GMT

PS: I mean that must Enhanced ShockBurst be enabled before an nRF24L01P will return any ACKs when it receives a packet in PRX mode? I just want to get it really straight, please. JimR

RE: Can I get some clarification regarding pipes and addresses?

JimR — Thu, 03 Aug 2017 22:01:32 GMT

Hi Hung Bui, I guess I must have been confused in reading the info on page 49 of the data sheet, because I thought I had to disable Enhanced ShockBurst for backward compatibility with the nRF24L01. So just to clarify, please, are you saying that the only way to get any ACKs at all from an nRF24L01P is to enable Enhanced ShockBurst -- and that's why I'm not getting any at present? JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Thu, 03 Aug 2017 12:58:18 GMT

Are you sure it's the instruction to make it compatible with nRF24L01 ? We don't have something like that in the datasheet. It's only the instruction to make it compatible with nRF2401 which doesn't support Enhanced Shockburst. The nRF24L01 is almost identical to the nRF24L01+ except for 250kbps mode and you need to call ACTIVATE function to enable Enhanced Shockburst features.

When you test using 2 nRF24L01P do you get ACK ?

RE: Can I get some clarification regarding pipes and addresses?

JimR — Wed, 02 Aug 2017 21:30:24 GMT

Hi again Hung Bui. Here's another (related) question, though. When I follow the nRF24L01+ datasheet to make the chip and module compatible with those using the earlier nRF24L01 chip, does this disable all ACKnowledgements altogether? I ask this because I don't seem to be getting any ACKs. So didn't the earlier chips do ACKs, or did you have to do them in your program? If you can help, do so please. JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Mon, 10 Jul 2017 15:08:45 GMT

@JimR : What you say is correct. It's the status BEFORE the command or data is received. If you want the most upto date you would either read the status register, or do a dummy command (NOP command).

My suggestion is to use a logic analyzer and track down what the Arduino code does on the SPI and you try to do the same thing on your code, then compare why there is a difference in the result.

RE: Can I get some clarification regarding pipes and addresses?

JimR — Sun, 09 Jul 2017 23:18:27 GMT

Thank you Hung Bui, for that helpful reply. I have tried following the code used in both the Arduino program and in the RF24 code library in which its functions are sourced, but this has proved to be very difficult. In the meantime, can you please answer another question. I understand that whenever you send commands or data to the nRF24L01 via the SPI interface, it returns the contents of the status register. But presumably what it returns is the contents of the status register BEFORE the command or data is received -- right? If this is so, it sounds like if you want to know the chip's status AFTER the command or data is received, you need to read from the status register again, straight afterwards. Can you please confirm that this is correct -- or explain why it isn't. Thanks, JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Fri, 07 Jul 2017 08:58:09 GMT

Yes it's correct. But when a device is in TX mode, it's doesn't mater which RX_ADDR_* are set. Same with PRX, when you are in RX mode, TX_ADDR doesn't take effective. Please try to set on PTX side TX_ADDR to 0xE7E7E7E7E7 and on PRX side, set RX_ADDR_P0 to 0xE7E7E7E7E7 .

Make sure you enable Pipe 0 as receiver pipe.

Please post your code.

If the module works fine with the Arduino, you can try to follow what is used on the Arduino firmware and test on your device.

RE: Can I get some clarification regarding pipes and addresses?

JimR — Thu, 06 Jul 2017 21:25:55 GMT

Yes Hung Bui, I have tested that I can write and read the registers on the chip normally, and I'm pretty sure that I am setting it up correctly on the RF side. The RF hardware side is also functioning OK, since I'm using commercial modules with a 'meandering track' PCB antenna -- and the modules work fine with Arduino microcomputers. But you didn't actually say whether the addressing scheme I described in the previous comment was right or wrong -- can you please answer my question! JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Thu, 06 Jul 2017 16:03:38 GMT

Sorry, I meant "Appendix A" not "Appendix 1".

The nRF24 can listen to 6 different pipes (6 address) at the same time, you don't have to match the pipe on the PTX with the pipe on PRX. They don't care about pipe, the address is what they use to match.

There are many reasons that your chips don't communicate. We can think of there could be smth wrong with the firmware you use to test the chip. Have you made sure you can write and read the register on the chip normally ? Have you make sure the RF hardware part is done correctly ? Can you send the schematic and layout ? And a close up photo of your board ?

RE: Can I get some clarification regarding pipes and addresses?

JimR — Thu, 06 Jul 2017 00:04:46 GMT

Hi again Hung Bui, I have tried to read the explanation in appendix A of the nRF24L01 datasheet, and frankly I still find it confusing. But I have tried configuring Radio 0 with its TX_ADDR address pipe set to C2C2C2C2C2 and its RX_ADDR_P0 pipe address set to E7E7E7E7E7, and then Radio 1 is configured with its TX_ADDR pipe set to E7E7E7E7E7 and its RX_ADDR_P1 address set to C2C2C2C2C2. So each radio's receive address is set to the transmit address of the other, with the idea that Radio 0 transmits to Radio 1 via pipe 0, and Radio 1 transmits to Radio 0 via pipe 1. BUT THEY STILL DON'T COMMUNICATE -- so what is wrong? All I can think of at present is that they might have to use the same pipe for communication each way -- but that seems crazy. JimR

RE: Can I get some clarification regarding pipes and addresses?

JimR — Wed, 05 Jul 2017 22:23:11 GMT

Hi Hung Bui,

Thank you for that comment, although it really wasn't very helpful at all. For a start, you suggested that I follow the instruction at 'Appendix 1' in the datasheet, whereas my copy of the datasheet has three appendices, labelled A, B and C. So there's a puzzle straight away, although even if I assume that you mean appendix B, this still doesn't talk about actual addresses -- only address widths! Your other questions also don't make clear whether you mean that the transmitting device needs to use the same pipe address as the receiver, or what. Frankly, it's a bit confusing. JimR

RE: Can I get some clarification regarding pipes and addresses?

Hung Bui — Wed, 05 Jul 2017 14:35:09 GMT

Hi JimR,

Why would you have the receiver pipe address different with the transmitter TX address ? How would they talk to each other if the addresses are different ?

I suggest you follow the instruction at appendix 1 in the nRF24L01 datasheet.

RE: Can I get some clarification regarding pipes and addresses?

JimR — Tue, 04 Jul 2017 23:04:59 GMT

Also, the problem I have with the Getting Started RF24 program is that it doesn't seem to be sending the data for transmission to the chip's TX FIFO -- yet transmission still takes place! JimR

RE: Can I get some clarification regarding pipes and addresses?

JimR — Tue, 04 Jul 2017 23:02:26 GMT

Hi, I probably should have noted that I am not using 'Enhanced Shockburst', because I want my 'radios' to be compatible with others using the nRF24L01 -- not just the nRF24L01+. I guess I don't know if 'regular' Shockburst does any auto acknowledgment anyway -- does it? Perhaps I still need to send an ACK 'manually'... Sorry about my muddle. JimR