Hi there, I'm currently not getting any further with my issue, I was hoping someone has ran into a similar problem, or can tell me how to best troubleshoot this..
Some information:
I created a custom pcb (I attached the schematics) with an atmega 328p and a RFM69HCW 868mhz module, and had 5 produced, which worked fine, then I proceeded to order 50 pieces.
I use the nodes to send some data to a base station, who in turn will reply with how many sleepcycles the node will need to complete before sending new data.
I have completed 12 of the 50 pcb's (soldering the wire antenna, burning atmega 8mhz avr bootloader, set the fuses correctly, upload the arduino sketch)
I'm currently testing them, and 6 work without any issues they send sensor data, receive the amount of sleepcycles, and go to sleep for that amount of time, as expected.
But the other 6 have a funky problem.. they send data to my base station but don't receive the response (The basestation tells me it is sending the response, same is with the working nodes)
While I was testing this, I was using the led on the pcb, if it blinks once with 200ms delay it received the data, if it blinks 4 times with 50ms delay I know it didn't receive the reply.
the code for this looks like this:
if (rf69.waitAvailableTimeout(500))
{
// Should be a reply message for us now
if (rf69.recv(buf, &len))
{
sleepCycles = buf[0] <<8;
sleepCycles |= buf[1];
blinkLed(1, 200);
}
}
else
{
blinkLed(4, 50);
//Timeout? try again in 15 minutes
}
so it looks like the waitAvailableTimeout is timing out, and it didn't receive the reply..
The strange part is, this only goes wrong when I use a battery, when I use the FTDI connector it works as expected.
First I thought I messed the pcb design up, but since I got 6 working (out of the 12 first) I guess that's not the problem.
For now my best guess is there is a resistor or capacitor in the battery circuit that is faulty, but it's so strange that sending data is working for these 6 pcbs..
Can anyone tell me how they would approach solving this? or has anyone had something similar with the RFM69HCW?
Are you using RadioHead?
Yes, I'm using the RadioHead Lib
One sidenote it's the RFM69HW
I have purchased a logic analyzer to compare the SPI traffic between a working rfm chip and a non working, the biggest difference I noticed is this, does anyone have any idea what this sequence is?
Non Working
(http://demo.tom-it.nl/non_working_chip.png)
Working
(http://demo.tom-it.nl/working_chip.png)
If it's RFM69, you could use my library and start from working examples.
Other than that the problem might be in hardware.