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RFM69CW Board issues

Added by davep almost 5 years ago

Hi folks

After lurking about JEElabs for a while, I recently dived into Jeenodes for a simple project. I want to have an outdoor JNu sensor report a status back to a central point in my house, but since I had a couple of Arduino boards lying around, and have some thick external walls to get a signal through, and there is no Jeenode available with an RFM69 module pre-fitted, I went for the RFM69CW board and a JNu with a RFM69 radio too.

But I’m having trouble at the first hurdle. The RFM69 board has no documentation of its own (I discovered that the link to documentation on the Shop catalog page is broken only after I ordered it), so I followed the RFM12 board docs to solder it together. Although, for a total newbie like myself, the lack of clear details for every component’s location took a fair bit of careful scrutiny of the photos to try and make sure the resistors were in the right places etc.

So I think I have it right - but it doesn’t work, so I can’t be sure. Any sketch hangs at a call to rf12_initialize() or rf12_config() (and yes I have included the RF69_COMPAT switch).

Given some of other traffic on here about RFM69 vs RF12, I’m unsure of whether it’s a software or hardware problem, though given that there’s basically no code in the sketch, I am thinking it must be a hardware issue. Is there any other way of testing whether the board is set up properly, other than having it initialize() properly ?

Assuming not, I would appreciate someone who knows more than i taking a look at the board I’ve made and seeing if there are any obvious problems with it, since to the best of my ability it looks fine to me.

Essentially I’m a bit stuck as to what to focus on next so would appreciate some help !

Thanks

Dave



Replies (12)

RE: RFM69CW Board issues - Added by JohnO almost 5 years ago

Have you loaded up a copy of RF12Demo sketch onto the JNu in order to configure the relevant radio settings in eeprom, node. group and band? Once this is set load up your new sketch.

RE: RFM69CW Board issues - Added by martynj almost 5 years ago

davep,

What test tools do you have access to? Multimeter? ’Scope?

RE: RFM69CW Board issues - Added by davep almost 5 years ago

martynj I have a multimeter handy, but no scope.

@JohnO I haven’t got to the point of trying to set up the JNu yet - was just trying to get the receiver working before trying to send anything. I intend to try programming the JNu through another Arduino as ISP, which now looks to be something of an adventure all of its own…

RE: RFM69CW Board issues - Added by JohnO almost 5 years ago

I’ll hang back for Martyn, I just wanted to make the point that rf12_config() requires eeprom values to be initialized by RF12Demo whereas rf12_initialize() operates from supplied values.

RE: RFM69CW Board issues - Added by martynj almost 5 years ago

davep,

Your board appears to have several places with solder splatter.  It is worth cleaning this up (toothbrush and alcohol work well) to eliminate the chance of any shorts between tracks. Usually the splatter is lightly embedded in the solder resist layer  but once in a while can penetrate through to the copper underneath and create an unwanted path.

For the important pins, the RFM69CW has an identical footprint to the RFM12B, so those build instructions are valid.
Looking at the pads on the radio module - one pad (SEL) appears not to be soldered (Count five down from the ANT pad). If counting and matching to this picture from the RF12 Wiki is a pain - solder them all.

The 5V supply to the regulator is coming through the flying lead to the leftmost connector pin, bent at right angles so that it does not mate with the Arduino header.  Insert your multimeter in this path and check the current draw before and after initialisation.

RE: RFM69CW Board issues - Added by davep almost 5 years ago

OK, I’ve now cleaned up the splatter, and soldered the SEL pad.

Upon checking the current draw at the VCC pad before and after initialisation, I get a steady 3.35V in both cases - running the init code doesn’t appear to be making any difference.

RE: RFM69CW Board issues - Added by JohnO almost 5 years ago

I think Martyn is looking for you to measure on the milli-amp setting on your meter, in series between the bent pin and the Arduino socket deprived of its pin. The meter will be a low resistance in this mode so be careful to stay in series with the load f the RFM69CW..

RE: RFM69CW Board issues - Added by Mars almost 5 years ago

Just to make sure: you are using this board in a 5V setting, as you have soldered the regulator and signal resistors?

AFAIK this configuration won’t work in a 3.3V setting.

RE: RFM69CW Board issues - Added by davep almost 5 years ago

Yes, I’m definitely using it in a 5V setting, and have checked that the Arduino board is indeed putting out 5V.

I’ve tried putting the meter in series as suggested, and whether the radio is turned on or not, the current draw is reading a flat zero, while the voltage is reading 3.75. I’m no expert, but this doesn’t seem right …

RE: RFM69CW Board issues - Added by martynj almost 5 years ago

davep,

The LDO will draw a few microamps even when there are no other components active on the board.
Have you checked the Arduino hook up?

Next check that there is 3.3V output from the LDO - the easiest place is to probe between the Vdd supply pin on the RF module and ground.

Until there is a correct supply rail and ground to the RF module, it is not going to reply on the SPI bus, causing ‘hangs’ at any attempt to initialise the module.

RE: RFM69CW Board issues - Added by davep almost 5 years ago

@Martynj

I think you’re asking me to check the same thing I reported last week - that the voltage between Arduino ground and the VCC pad on the RF module (next to the antenna pad) is 3.35V, and on checking it again, it still is. I don’t know if it’s significant, but the bottom two pads on the same side of the RF module are also showing a voltage difference too (0.43 on the bottom one, 3.45 on the one above) but as these pads are unlabelled I’m not sure if that’s significant or not. No other pads are registering anything.

RE: RFM69CW Board issues - Added by JohnD almost 5 years ago

You may have solved this by now but if you have not, I would say you have a cold joint. In particular look the connections over on the regulator ant the electrolytic. Otherwise look for places where the solder
seems to pile too high. It should flow better if you are using flux. Check continuity from the top of the board or bottom to the actual solder clump on the other side. Also on the misalignment of the radio to the board
it is real easy to get solder creeping over to the adjacent pad and you can’t see it, so check for shorts on adjacent pads. Good Luck

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