[Solved] PiFace RTC not working (on a rpi2)

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[Solved] PiFace RTC not working (on a rpi2)

Postby zebul666 » Fri Aug 24, 2018 10:55 pm

hi.

I have a PiFace (shim) RTc clock that I try to use on an old rpi2 (b+)

So I have enabled i2c in /boot/config.txt with

Code: Select all
dtparam=i2c=on


Then, for the moment I do that manually
Code: Select all
modprobe i2c-dev
modprobe i2c:mcp7941x

and finally
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echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device


but then I have no rtc device.

Moreover when I run
Code: Select all
 i2cdetect -y 1
, I got no device found on the bus.

So I wonder what do I do wrong ? I followed what is said in this thread viewtopic.php?f=31&t=8243

I wonder if the piface RTC is defective. By carefully looking at it, it seems to lack a soldering at one point. Image The photo make it non obvious because it appears as if there is a big bulk of soldering whereas there is none.
If I compare that to the official photo of it Image

Any help ?
Thanks
Last edited by zebul666 on Sat Aug 25, 2018 1:42 pm, edited 1 time in total.
zebul666
 
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Re: PiFace RTC not working (on a rpi2)

Postby zebul666 » Sat Aug 25, 2018 1:15 pm

So the PiFace RTC clock seems to be fine as the device is detected on the I2C bus when plugged in into a rpi3 Gpio pins

I run also pintest and gpiotest that found nothing wrong on my rpi2.
I have also unlaoded video driver for the camera, just in case.

Still nothing on the I2C bus.
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Re: PiFace RTC not working (on a rpi2)

Postby zebul666 » Sat Aug 25, 2018 1:42 pm

Ok. So it's a bad contact of the piface board on the gpio pins. just moving it up, make the device appears on the bus.

I need to find a way to fix that. so that the device does not disappear from the bus when the rpi is moved.

Any idea ? without soldering.
zebul666
 
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Re: [Solved] PiFace RTC not working (on a rpi2)

Postby TheSaint » Sat Aug 25, 2018 11:35 pm

Soldering is require. Perhaps you may solder a header to the RTC module and connect to the SBC with jumpers.
Like these
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Re: [Solved] PiFace RTC not working (on a rpi2)

Postby zebul666 » Mon Aug 27, 2018 1:18 pm

Yes i am thinking at soldering.
But I would rather go at directly soldering the piface to the rpi on its gpio pin.
I don't think I have to solder every hole, right. Only some of them are used at all ?

So I think may be GPIO pin 1 and 5 and the ground at 6 ?? I don't know which ones are used. Nothing is in the manual.

If I do it your way, I will need jumpers for every pin of the header, right, That's a lot of them ?? If not then that's the same question as above ? which one do I need to connect ?
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Re: [Solved] PiFace RTC not working (on a rpi2)

Postby TheSaint » Mon Aug 27, 2018 1:57 pm

Well I mean you should provide the header to the PiFace and then use the breadboard jumpers to link RPi with the PiFace. Just the pins which are needed.
Otherwise you might solder the wires on the PiFace and plug the connection to the RPi.
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