Installing Code for PiFace Real Time Clock

Here's my revised script, unfortunately I cant test it on a pi zero because I don't have one, nor do I have the real time clock module. The script isn't reliant upon the model or revision of the raspberry pi anymore. It finds the hardware i2c port from the devices list so it should be compatible with all models and revisions of the pi to date. If a raspberry pi is introduced in the future that utilizes multiple i2c ports/buses then this script would need to be modified but for the time being it should work fine.

As a test on my Raspberry Pi 3 Model B, a ran the revised script, restarted and then searched for the MCP7941x device in the i2c-dev system folder, sure enough it was there. If I had the physical realtime clock module, this is the part of the system that would communicate with it.

Finally to the revised script:

pifacetest.sh

#!/bin/bash
#: Description: Enables the required modules for PiFace Clock.
# a modification of a script at:
# https://github.com/piface/PiFace-Real-Time-Clock/blob/master/install-piface-real-time-clock.sh
# this modification includes functionality with Raspberry Pi Zero
# by making the model and revision checking redundant
# credit for the original script goes to tompreston & pat3df at GitHub
# modifications made by Lucie Tozer

#=======================================================================
# NAME: check_for_i2c_tools
# DESCRIPTION: Checks if i2c-tools is installed.
#=======================================================================
check_for_i2c_tools() {
    dpkg -s i2c-tools > /dev/null 2>&1
    if [[ $? -eq 1 ]]; then
        echo "The package `i2c-tools` is not installed. Install it with:"
        echo ""
        echo "    sudo apt-get install i2c-tools"
        echo ""
        exit 1
    fi
}

#=======================================================================
# NAME: final_message
# DESCRIPTION: prints instructions for setting the clock
#=======================================================================
final_message(){
    echo "Now *reboot* and set your clock with:"
    echo ""
    echo '    sudo date -s "14 JAN 2014 10:10:30"'
    echo "    sudo hwclock --systohc"
    echo ""
}

#=======================================================================
# NAME: get_i2c_device
# DESCRIPTION: Obtains the working i2c port from the /dev file system
#=======================================================================
get_i2c_device(){
    I2C_DEVICE=$(ls /dev | grep "i2c")
    echo "i2c device on this model = " $I2C_DEVICE
    
    if [[ $I2C_DEVICE == "i2c-1" ]]; then
        I2C_PORT_NUMBER=1  # i2c-1
    else
        I2C_PORT_NUMBER=0  # i2c-0
    fi
    
    if [[ ! -e /sys/class/i2c-dev/i2c-$I2C_PORT_NUMBER ]]; then
        echo "Enable I2C by using:"
        echo ""
        echo "    raspi-config"
        echo ""
        echo "Then navigate to 'Advanced Options' > 'I2C' and select 'yes' to "
        echo "enable the ARM I2C interface."
        echo ""
        echo "Please Restart This Script Once The I2C Interface Has Been Enabled"
        echo "EXITING..."
        exit 1
    fi

}

#=======================================================================
# NAME: start_on_boot
# DESCRIPTION: Load the I2C modules and send magic number to RTC, on boot.
#=======================================================================
start_on_boot() {
    echo "Create a new pifacertc init script to load time from PiFace RTC."
    echo "Adding /etc/init.d/pifacertc ."



    cat > /etc/init.d/pifacertc  << EOF
#!/bin/sh
### BEGIN INIT INFO
# Provides:          pifacertc
# Required-Start:    udev mountkernfs \$remote_fs raspi-config
# Required-Stop:
# Default-Start:     S
# Default-Stop:
# Short-Description: Add the PiFace RTC
# Description:       Add the PiFace RTC
### END INIT INFO

. /lib/lsb/init-functions

case "\$1" in
  start)
    log_success_msg "Probe the i2c-dev"
    modprobe i2c-dev
    # Calibrate the clock (default: 0x47). See datasheet for MCP7940N
    log_success_msg "Calibrate the clock"
    i2cset -y $I2C_PORT_NUMBER 0x6f 0x08 0x47
    log_success_msg "Probe the mcp7941x driver"
    modprobe i2c:mcp7941x
    log_success_msg "Add the mcp7941x device in the sys filesystem"
    # https://www.kernel.org/doc/Documentation/i2c/instantiating-devices
    echo mcp7941x 0x6f > /sys/class/i2c-dev/i2c-$I2C_PORT_NUMBER/device/new_device
    log_success_msg "Synchronise the system clock and hardware RTC"
    hwclock --hctosys
    ;;
  stop)
    ;;
  restart)
    ;;
  force-reload)
    ;;
  *)
    echo "Usage: \$0 start" >&2
    exit 3
    ;;
esac
EOF
    chmod +x /etc/init.d/pifacertc

    echo "Install the pifacertc init script"
    update-rc.d pifacertc  defaults
}

#=======================================================================
# MAIN
#=======================================================================
# check if the script is being run as root
if [[ $EUID -ne 0 ]]
then
    printf 'This script must be run as root.\nExiting..\n'
    exit 1
fi



I2C_PORT_NUMBER=0
I2C_DEVICE=""

check_for_i2c_tools &&
get_i2c_device &&
start_on_boot &&
final_message

I kept as much of the original as possible so it should read similarly and changes should be easily noticed.

here's an easy way to install:

1) copy the script to clipboard

2) log on to your raspberry pi with a terminal

3) cd ~/

4) nano ./pifacetest.sh

5) Paste clipboard into nano (ctrl + shift + v)

6) wait a few seconds for nano to buffer the clip board

7) once clipboard has pasted press ctrl + o to write the file

8) press ctrl + x to exit nano

9) sudo chmod +x ./pifacetest.sh to enable the file to be executed

10) finally run the script sudo ./pifacetest.sh

If your having trouble creating the file, Im happy to upload it to a temporary location so you can use wget to download it directly to the raspberry pi.

Dear Mr. Oakes,

In the past 12 hr, I got a couple of responses pertaining to the RPi Zero issue regarding PiFace RTC. I am impressed that so much knowledge can be attained with the cat /proc/cpuinfo command. As I am just a beginner in Raspberry Pi application and its language (I realize its a subset of Linux), I guess I'll call it raspbian language. [A brief history- started with RPi Model 2 / wheezy w/ PiFace RTC all went well but I had to modify the code to use 3.5- and 7- inch raspberry Pi screens. I am into RPi zero Rev 1 installations using Jessie but have had no success in adding PiFace RTC thru /etc/init.d/pifacertc . I plan to install RPi zero Rev 2 with the new Jessie w/ Pixel installation when this issue is resolved. It appears that your suggestions about modifying the code " manualy" but I am very limited knowledgwise in accomplishing the task alone. With the help of ms tozer and now a response from Jan Crumps (please see other posts), I am assuming that a code revision is warranted. I also have RPi 3's planned for installation and hope to find out by then what I'm doing.]

I will execute >>  run i2cdetect -l << on my RPi zero's shortly. I see that the only model 512 MB RPi Zero (I assume Ver 1) is a Sony Device. I don't know what my RPi Zero (Ver 2) which includes a camera interface) hardware info and whether the pending changes will be compatible.

Dear Mr. Elkins

I believe that you are spot-on the problem I am having with Installing PiFaceRTC on Rpi Zero (ver 1). Ms Tozer and jan crumps have responded quickly and pointedly at my (and others) issue. I agree on rewriting the code " manually" but I am afraid I am very limited knowledgwise in accomplishing this task alone. I believe that a code revision is imminent and I will patiently await a revision without reporting the bug (I may not be clear of what to request). I just am not knowledgeable to apply the code you wrote above (which is understandable to me) into a executable (I don't know if that's correct verbage) complete code and not know what to do with it. Please read all other posts on this thread because they seem to be very applicable when combined. Thank you very much. Frank.

Dear Ms Tozer,

During the time I was writing the responses to the number of experts I got this message. I truly appreciate the help from all and I will try it on my physical RPi Zeros and PiFace RTC. I don't know whether this will completely install the RTC and as a result it may take a few days (trial and error). However, as you suggested if you can generate a website to expedite the code capture directly to my device terminal,  I would greatly appreciate it. In  addition, I apologize for not understanding this forums language and you may or may not be attached to "violet" and \or "Jan Cump". (Disregard if you are confused).

Also, as stated in one of Peter Oakes replies, even though the Zero's I've been testing all have the same Mfgr (Sony), I have two other RPi Zeros (model 2- ones a camera interface). I have no knowledge that PiFace RTC will be be successfully installed with your code but I will march on faithfully.

Again all the other replies in this thread should be read for their noble efforts, enthusiasim and participation in this issue.

Thanks again, Frank

Ive uploaded the modified file to http://www.uk-robotics.co.uk/temp/pifacertctest.sh provided you pi is connected to the internat, you can download it easily to your raspberry pi by opening a terminal and the typing:

cd ~/

wget http://www.uk-robotics.co.uk/temp/pifacertctest.sh

to run the file type sudo ./pifacertctest.sh

If you have any problem with executable permissions, type chmod +x ./pifacertctest.sh and then try running it again

I've seen a few variations of my name floating around in this thread (unusual for a Raspberry Pi topic). What did I say/do?

looking at response and new script, it won't matter what the model of PI is, what will matter is if the pi is exposing  I2C-0 or I2C-1 and selecting the appropriate one as found in the test

this could easily work on non PI units like ApplePI, OrangePi, BannanaPI etc etc.

"Ms. Tozer",

Suggestion: In the "start" function of /etc/init.d/pifacertc, if an error occurs, quit immediately with the appropriate error message (log_failure_msg).  There is no point in continuing with the remaining commands when it isn't going to work.  And, it might cause other issues as mentioned in the i2cset man page.

For example, I simulated a clock not connected condition.  Actually, I don't have the hardware.  I was able to install simply because I enabled i2c in raspy-config.

My syslog entries from system startup:

Nov  6 14:36:02 raspbian pifacertc[1465]: Probe the i2c-dev.

Nov  6 14:36:02 raspbian pifacertc[1465]: Calibrate the clock.

Nov  6 14:36:02 raspbian pifacertc[1465]: Error: Write failed

Nov  6 14:36:02 raspbian pifacertc[1465]: Probe the mcp7941x driver.

Nov  6 14:36:02 raspbian pifacertc[1465]: Add the mcp7941x device in the sys filesystem.

Nov  6 14:36:02 raspbian pifacertc[1465]: Synchronise the system clock and hardware RTC.

Nov  6 14:36:02 raspbian pifacertc[1465]: hwclock: Cannot access the Hardware Clock via any known method.

Nov  6 14:36:02 raspbian pifacertc[1465]: hwclock: Use the --debug option to see the details of our search for an access method.

Nov  6 14:36:02 raspbian systemd[1]: pifacertc.service: control process exited, code=exited status=70

Nov  6 14:36:02 raspbian systemd[1]: Unit pifacertc.service entered failed state.

You can catch the exit code of each step to see if that step was successful or not.

Frank, you have my permission to call me "Richard" !!

Jan, how can we talk about you behind your back if you keep on peeking over our shoulders???