Understanding readData using RF69HCW and POCSAG in esp-idf

[lazeeeer]

Im having an issue where it doesn't seem like calling readData() from the pager class is removing data from the module buffer.

int get_message(uint8_t* byteBuffer, size_t bufferLen )
{
    size_t len;
    uint32_t rec_address;

    // reading data
    int state = pager.readData(byteBuffer, &len, &rec_address);

    if (state != RADIOLIB_ERR_NONE)
    {
        printf("could not read a message for some reason... : %d\n", state);
        return state;   // returning RadioLib error code for debug
    }
    else {
        return RADIOLIB_ERR_NONE;
    }
}

this function will usually return the received message once, however afterwards it seems to be getting stuck BACK inside the readData function again as it thinks there is more data available?

im wondering is there is a procedure i should be following when receiving POCSAG transmissions so that the module will read AND remove a message from its buffer.

[jgromes]

I don't think I've tried POCSAG reception with RF69 so there could be something broken in there. The best starting point is to enable protocol debug which will print out all the received data.

[lazeeeer]

sure ill give the protocol debug a try. Would you be able to confirm though that readData() should be removing one of the received messages from the RF69 buffer? In the meantime ill look into the protocol debugger and post any progress I find

Thank you for your fast response!

[jgromes]

That's not really how it works, it is using a circular buffer, but the pointers are getting updated correctly. This is not specific for RF69 and I know SX127x can receive pager data so I doubt this is the actual cause. Also, you don't need my confirmation for this, you can check the source directly:

RadioLib/src/protocols/PhysicalLayer/PhysicalLayer.cpp

Lines 431 to 437 in bedab1a

	uint8_t PhysicalLayer::read(bool drop) {
	if(drop) {
	dropSync();
	}
	this->bufferWritePos--;
	return(this->buffer[this->bufferReadPos++]);
	}