PiFace Shim RTC not recognised on a RPi B+

Question

New stock Raspberry Pi B+, new stock PiFace Shim RTC, fresh battery, all updates applied

Here's the error messages

pi@raspberrypi ~ $ hwclock

hwclock: Cannot access the Hardware Clock via any known method.

hwclock: Use the --debug option to see the details of our search for an access method.

pi@raspberrypi ~ $ sudo hwclock

hwclock: Cannot access the Hardware Clock via any known method.

hwclock: Use the --debug option to see the details of our search for an access method.

pi@raspberrypi ~ $ sudo hwclock -s

hwclock: Cannot access the Hardware Clock via any known method.

hwclock: Use the --debug option to see the details of our search for an access method.

pi@raspberrypi ~ $ sudo hwclock --debug

hwclock from util-linux 2.20.1

hwclock: Open of /dev/rtc failed: No such file or directory

No usable clock interface found.

hwclock: Cannot access the Hardware Clock via any known method.

Cheers

clem57 · Answer

Please note: must solder shim to RPi! This may not be obvious to some folks,

piknot · Answer

Mike ...

Not sure what I did correctly or in-correctly but I am now getting UU in line 6f (I think I may of had keyboard problems with VNC). Now the next test for me is to get the correct time set (always fun being a NOOB).

mconners · Answer

Well, take a look at the blog post I made and make sure you have everything in place.

A couple of things to check:

lsmod | grep i2c

that should return

i2c_bcm2708

i2c_dev

type

grep i2c /boot/config.txt

that should return

dtparam=i2c_arm=on

make sure it doesn't have a # in front of it

after doing

sudo modprobe i2c:mcp7941x

lsmod | grep i2c

should return

i2c:mcp7941x

and the previous 2 entries

If any of those do not return the proper results, then there is an issue

Mike

mconners · Answer

also, after the modprobe, when you have determined that the module has loaded do ls /dev/rtc* to make sure it created the device nodes that should return /dev/rtc /dev/rtc0 Mike

mconners · Answer

actually, I take that back, it's actually the line echo mcp7941x 0x6f > /sys/class/i2c-adapter/i2c-1/new_devic e that creates the device. Mike

PiFace Shim RTC not recognised on a RPi B+

Top Replies