I am using RAK3172 in P2P mode with Nucleo-WL55JC1. When I put 3172 in receive mode and transmit some data like simple “1230” from Nucleo-WL55JC1, I receive “+EVT:RXP2P RECEIVE ERROR”.
The setting for frequency and other parameters are here: AT+P2P=868000000:7:0:0:255:20
Are the parameters the same? This is the sequence of parameters in AT+P2P command <Frequency>:<Spreading Factor>:<Bandwidth>:<Code Rate>:<Preamble Length>:<TX Power>
Did you configure the P2P continuous mode using AT+PRECV=65534?
Did the +EVT:RXP2P RECEIVE ERROR callback happen when you transmit from Nucleo-WL55JC1 board or it just shows suddenly after a while?
Yes, the parameters are the same for both of the boards.
Yes, I had configured it in continuous mode with AT+PRECV=65534.
No this message is not happening suddenly when I transmit from Nucleo-WL55JC1 then only RAK3172 receives garbage data and at the end, it shows +Evt: RXP2P ERROR.
Will it be possible to verify with another board if Nucleo board is really transmitting something? On the other end, RAK3172 should be receiving something (if other board is used as transmitter)?
Try and change your settings from AT+P2P=868000000:7:0:0:255:20 to something more reasonable like AT+P2P=868000000:7:0:0:8:20.
255 bytes of preamble not only doesn’t make much sense, but it also takes up all the space for transmission – packets are limited to 255 bytes, preamble included. An eight-byte preamble is standard, and much more reasonable.
@carlrowan The example in the online docs is AT+P2P=868000000:12:0:3:200:14 and is partly responsible for this. There is no scenario that I can think of where a 200-byte preamble is viable. Maybe the docs should be updated to something more common and reasonable, like AT+P2P=868000000:12:0:3:8:14…
Thanks for the suggestion @Kongduino . Your point is very reasonable. I will update the RUI3 AT docs. On our modules quick start guide, we use SF7. Might be better as well than SF12 since it is common on initial test on modules to be close to one another.
My setting in Power is +20dBm. So due to this, did any issue happen?
Because when I looked up the datasheet of STM32WLE5CC, the low power configuration is limited to +15dBm, and for high power, it is maximum to +22dBm.
As RAK3172 uses an RFO_HP pin in the transmitter section. Please correct me if I am wrong.
No. As I said, the problem is with the preamble length. You can indeed use Tx 20 (or 22). I do all the time. But a preamble of 255 bytes is a no no. Use something like AT+P2P=868000000:7:0:0:8:20. With an 8-byte preamble.
Please respond to this query.
While testing, I change some parameters for P2P, they are as follows:
Frequency: 868MHz
Spreading Factor: 7
Bandwidth: 125KHz
Coding Rate: 4/5
Preamble Length: 10
Power: 15dBm
(These parameters I set in the RAK module).
On the other hand, I set the same parameters in the Nucleo-WL55JC board just 1 change is there. The coding rate is 4/8.
I send “1122334455” from RAK the other node receives it. But RAK is not able to receive any message from the Nucleo-WL55JC.
Also, if I send other messages than the mentioned one. At the receiver end it gives CRC_IRQ_Error.