Author Topic: RFM69W Module stops receiving data (partial brick)  (Read 1748 times)

Lensdigital

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RFM69W Module stops receiving data (partial brick)
« on: June 13, 2015, 08:19:05 PM »
I'm working on a custom ATMega328p based board with RFM69W module.  It's been working great, I soldered probably 5 boards now. But I'm having weirdest issue with RFM69 on last one...
RF module seems to be getting partially bricked, specifically part of the circuit that receives data.
It transmits ok, but just does not receive anything...
First time it happened when I just soldered everything together, it was transmitting but not receiving ACK. 
I checked every millimeter of the board, and finally concluded it was bad RFM69 module. So I de-soldered it and, and soldered new one. Without even touching code in the flash it was working!  Sent a faulty one to the supplier.
That board has been working no-stop for almost a month, and now I have same issue. RFM69 refuses to receive data...  Something obviously fried, but I have no idea how. Has anyone seen something like this?
This is extremely frustrating as there's only one RFM supplier in the US and this is not the first time I'm having issue with these chips (i.e. some 433Mhz were mislabeled as 915 Mhz)...
« Last Edit: June 16, 2015, 09:41:04 AM by Lensdigital »
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Felix

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Re: RFM69W Module stops receiving data (partial brick)
« Reply #1 on: June 22, 2015, 07:37:44 AM »
I have not experienced anything like this. I have had a node that was weather exposed stop working or work erratically because of different weak wiring connection issues. I switched to a solid battery connector (JST) and cleaned the joints and applied electronic varnish over the board and now everything is working solid again. I think in your case it's something else. If all your boards are the same, and only one is giving you issues it can be either bad RFM modules in a row (but its weird to have all of them fail on 1 board and not the others).
When you say it refuses to receive, is the transmit part still working?
That may be possible if the temperature is very different between your sender and this receiver (frequency temp drift, discussed in one of the sticky topics).
Does restarting the board help?

Lensdigital

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Re: RFM69W Module stops receiving data (partial brick)
« Reply #2 on: June 22, 2015, 09:36:37 AM »
Cool idea using varnish!

Yeah on that board I can transmit with no issues. It just won't receive anything. I just realized it didn't die suddenly with second RFM module. It would work for few hours and then stop receiving. I always assumed it was something with the code. Week after erratic behavior it stopped receiving at all. No restart doesn't help, it seems to be permanently bricked (well read below, it actually kind of started to work again recently).  Perhaps an EMP fried part of the circuit (i.e. from lightning storm or something). Also it's indoor unit.
Now for the weird part. When I wrote that original post, RX was dead, no question about it. Whole board was just put aside and labeled as "do not use". 2 days ago I ran out of boards for project I was using and reluctantly picked one "bad" one not expecting radio to work (I just needed to finish my TFT LCD menu program). I updated low fuses to FF so it will run at 16 Mhz (it was 8 Mhz before).  Just for heck it of it I checked radio and it was working again.  It's like it's possessed or something :) I'll see how long it will last this time, but maybe messing up with ISP programming somehow reset something in firmware of RFM69W chip...
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TomWS

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Re: RFM69W Module stops receiving data (partial brick)
« Reply #3 on: June 22, 2015, 10:12:37 AM »
Is the troublesome board in a humid location?  I've had issues with boards quitting due to corrosion causing bridges between ATmega pins.  A good washing with 91% IPA and a dip in Spar Varnish solved the problem.

Tom

Lensdigital

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Re: RFM69W Module stops receiving data (partial brick)
« Reply #4 on: June 22, 2015, 10:16:13 AM »
Is the troublesome board in a humid location?  I've had issues with boards quitting due to corrosion causing bridges between ATmega pins.  A good washing with 91% IPA and a dip in Spar Varnish solved the problem.

Tom
Nah it's in my room, humidity is never about 50%.  Other sensor are in various outdoor locations, but they didn't give me much issues. Well except for one. I had it without any enclosure in the shed on the table for few months. It stopped transmitting so I went to check it out.  Bird somehow got into the shed and pooped on the board :)  Shorted battery to the ground  ;D

As far the original issue, if you think about it, it cannot be anything physical on the host PCB. There're no dedicated RX/TX lines to the RFM69 module.  All communication is done with same SPI pins, so if TX works and RX doesn't it can't be connection, gotta be something inside the RFM module. At least that's what logic dictates :)
« Last Edit: June 22, 2015, 10:20:03 AM by Lensdigital »
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TomWS

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Re: RFM69W Module stops receiving data (partial brick)
« Reply #5 on: June 22, 2015, 12:21:18 PM »
I had it without any enclosure in the shed on the table for few months. It stopped transmitting so I went to check it out.  Bird somehow got into the shed and pooped on the board :)  Shorted battery to the ground  ;D
You don't suppose the bird got it in the end, do you?
As far the original issue, if you think about it, it cannot be anything physical on the host PCB. There're no dedicated RX/TX lines to the RFM69 module.  All communication is done with same SPI pins, so if TX works and RX doesn't it can't be connection, gotta be something inside the RFM module. At least that's what logic dictates :)
Boy, I wish I had a buck for every time someone told me in my career that "It can't possibly happen."  Wait!  Hmmmm, maybe I did make a bunch of bucks in those cases.  ;)

Tom