PiFace RTC on Raspberry Pi2: still losing time on reboot!

You did not install startup script. See https://github.com/piface/PiFace-Real-Time-Clock for install script.

Clem

Hi Clem,

Thank you.

Yes, I installed the script, either automatically (connected to the internet) and manually (procedure described in the link you provided). Unfortunately, nothing is changed..

After installing the script with

$ sudo ./install-piface-real-time-clock.sh

This message appears:

Changing /etc/rc.local to load time from PiFace Clock.
Now *reboot* and set your clock with
sudo date -s "14 JAN 2014 10:10:30"

So, I enabled the I2C by running

$ raspi-config

as described in the link you provided, then I rebooted and set the date with sudo date -s ...

Then:

sudo reboot

The new date seems to be not retained!

$ date

Gives to me:

gio 1 gen 1970, 01.00.18, CET

It still not working !

I checked the i2c with:

$ i2cdetect -y 1

this is the output:

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU
70: -- -- -- -- -- -- -- --

As far as I remember, this means that the PiFace RTC seems to be well detected...

I really can't understand where can be the problem, what am I doing wrong?

Thanks in advance,

Andrea

Do you have pullups on the I2C lines, if not you should, they will help alot

about 5K-10K should work if the RTC is closs to the PI

Do you have pullups on the I2C lines, if not you should, they will help alot

about 5K-10K should work if the RTC is closs to the PI

Just looked at the board and it appears to have some so perhaps a different problem ??

Thanks Peter,

yes, perhaps it's a different problem.

For testing purpose, I tryied to set the date with:

sudo date -s "14 jan 2016 08:55:30"

then I copy the time to the RTC with:

sudo hwclock -w

Then I read the RTC with:

sudo hwclock -r

Ok, the time displayed is correct.

After that, I shut down, wait for five minutes and I power up.

I try to read the RTC once more:

sudo hwclock -r

It gives:

gio 1 gen 1970, 01.00.31, CET

and sudo hwclock -r gives:

hwclock: The Hardware Clock registers contain values that are either 
invalid (e.g. 50th day of month) or beyond the range we can handle (e.g. Year 2095).

So the time has not being retained! I really don't know where the problem can be

Please help!

#=======================================================================

# NAME: start_on_boot

# DESCRIPTION: Load the I2C modules and send magic number to RTC, on boot.

#=======================================================================

start_on_boot() {

  echo "Changing /etc/rc.local to load time from PiFace Clock."

  # remove exit 0

  sed -i "s/exit 0//" /etc/rc.local

  if [[ $RPI_REVISION == "1" ]]; then

  i=0 # i2c-0

  else

  i=1 # i2c-1

  fi

  cat >> /etc/rc.local << EOF

modprobe i2c-dev

# Calibrate the clock (default: 0x47). See datasheet for MCP7940N

i2cset -y $i 0x6f 0x08 0x47

modprobe i2c:mcp7941x

echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-$i/device/new_device

hwclock -s

EOF

}

The script above is not setting /etc/rc.local correctly. Please show the contents here. Ty

Clem

Hi Clem,

where have to be placed the script you posted? Is it automatically executed at the startup?

My /etc/rc.local contains the code below (is it correct? Perhaps some problems here?)

_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi


modprobe i2c-dev
# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s
modprobe i2c-dev
# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s

#Andrea
echo mcp7941x 0x6f > sys/class/i2c-adapter/i2c-1/new_device
( sleep 2; hwclock -s ) &

modprobe i2c-dev
# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s

#added by myself
echo mcp7941x 0x6f > sys/class/i2c-adapter/i2c-1/new_device
sudo hwclock -s

modprobe i2c-dev
# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s

#added by myself
echo mcp7941x 0x6f > sys/class/i2c-adapter/i2c-1/new_device
sudo hwclock -s
modprobe i2c-dev

# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s
modprobe i2c-dev
# Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s

Thanks again!

Ok you have too much. remove all up to last "#  Calibrate" using nano. save and reboot. Should work

Clem

I will try and let you know if it can solve the problem. Thanks!

Hi Clem,

I modified my /etc/rc.local according with your tip. At the first reboot the time was ok! But with the successive shutdown and reboots, time and date was still not retained! Is it possible?

Now my /etc/rc.local is:

#Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
   printf "My IP address is %s\n" "$_IP"
fi

#Calibrate the clock (default: 0x47). See datasheet for MCP7940N
i2cset -y 1 0x6f 0x08 0x47
modprobe i2c:mcp7941x
echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-1/device/new_device
hwclock -s

Do you think it should be ok?

Thanks.

You do have a battery in holder, right?

Clem

Yes,

I just check it now with a multimeter...