RPi/install/real_time_clock_RTC

#

2020 05 27 + init RTC@rpi /A

2022 03 19 + published on https://github.com/InstallAndUse/RPi /A

#

enable modules

sudo nano /etc/modules

i2c-bcm2708
i2c-dev

nano /etc/modprobe.d/raspi-blacklist.conf

comment

blacklist spi-bcm2708

blacklist i2c-bcm2708

#

SPI (DS1302)

#

#

i2c (DS1307, PCF8523, DS3231)

# apt install i2c-tools i2cdetect -y 1 modprobe rtc-ds1307 echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device

read RTC

hwclock -r

write RTC

hwclock -w

add to boot

nano /etc/init.d/hwlock.sh

unset TZ at top add

do
  echo ds1307 0x68 >> $bus/new_device;
  if [ -e /dev/rtc0 ];
  then
    log_action_msg "RTC found on bus `cat $bus/name`";
    break; # RTC found, bail out of the loop
  else
    echo 0x68 >> $bus/delete_device
  fi
done
}

near case, chage

case "$1" in
    start)
        # If the admin deleted the hwclock config, create a blank
        # template with the defaults.
        if [ -w /etc ] && [ ! -f /etc/adjtime ] && [ ! -e /etc/adjtime ]; then
            printf "0.0 0 0.0\n0\nUTC" > /etc/adjtime
        fi
        init_rtc_device

            # Raspberry Pi doesn't have udev detectable RTC
        #if [ -d /run/udev ] || [ -d /dev/.udev ]; then

update-rc.d hwclock.sh enable update-rc.d fake-hwclock remove

remove fake hardware clock, used in RPi

sudo su apt-get -y remove fake-hwclock update-rc.d -f fake-hwclock remove systemctl disable fake-hwclock

refs:

https://cdn-learn.adafruit.com/downloads/pdf/adding-a-real-time-clock-to-raspberry-pi.pdf

Books:

• Anton's bookshelf

Books:

• Anton's bookshelf