====== How to PCF8563 RTC Module on the Odroid C2 ======

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{{http://www.hardkernel.com/main/_Files/prdt/2016/201604/201604071438375783.jpg}}
{{http://www.hardkernel.com/main/_Files/prdt/2016/201604/201604071404256735.jpg}}

  * {{en:c1:pcf8563_rtc_shield_rev0.1.pdf|RTC Shield Schematic}}

===== Preparations =====
  * ODROID-C2
  * uSD-Card  => over 8GB or eMMC Module
  * PCF8563 RTC Module
  * Linux Kernel 3.14.65-66 or higher.[[http://odroid.com/dokuwiki/doku.php?id=en:c2_ubuntu_release_note_v1.2#how_to_update_the_kernel_and_system|how-to-update-kernel]]


===== Configuration =====
==== Ubuntu ====
  - Insert the RTC Shield on your C2 as the above pictures and turn on the system.
  - Enable RTC Shield driver in Device Tree file and add the I2C driver <code>
odroid@odroid:~$ sudo apt install device-tree-compiler
odroid@odroid:~$ sudo fdtput -t s /media/boot/meson64_odroidc2.dtb /i2c@c1108500/pcf8563@51 status "okay"
odroid@odroid:~$ echo "aml_i2c"|sudo tee -a /etc/modules
odroid@odroid:~$ echo "rtc_pcf8563"|sudo tee -a /etc/modules
odroid@odroid:~$ reboot</code> 
  - Check the I2C & RTC module status after reboot:   <code>odroid@odroid64:~$ cat /etc/modules                                             
# /etc/modules: kernel modules to load at boot time.                            
#                                                                               
# This file contains the names of kernel modules that should be loaded          
# at boot time, one per line. Lines beginning with "#" are ignored.             
aml_i2c

odroid@odroid64:~$ ls /dev/rtc                                                  
/dev/rtc

odroid@odroid64:~$ lsmod
.....
rtc_pcf8563             3996  0
aml_i2c                16898  0
.....
</code> 
  - Next you want to update system Time/Calendar from the HW RTC at boot time by editing /etc/rc.local file<code>
odroid@odroid:~$ sudo nano /etc/rc.local

if [ -f /aafirstboot ]; then /aafirstboot start ; fi

hwclock -s

exit 0
odroid@odroid:~$</code> Add the following at the bottom of the page above exit 0. ^x exit and save the file. Reboot your ODROID-C2. <code>odroid@odroid:~$ sudo reboot</code> If everything worked correctly the RTC on ODROID-C2 should be initialised on boot and the current date and time will be loaded into Linux. You need to check the existence of "rtc-pcf8563" in the output of "lsmod" command when the HW RTC doesn't work correctly.
  - You can check the current time on the RTC on ODROID-C2 with: <code>odroid@odroid:~$ sudo hwclock -r</code> If this is the first time you have run the RTC on ODROID-C2 it will display a date of APR 20th 2016.
  - If the ODROID-C2 is connected to the internet the correct date and time should be set automatically otherwise you can set the current date and time using: <code>odroid@odroid:~$ sudo date -s "20 APR 2016 18:00:00" </code> You can check the current linux date with the command (date).
  - To save the date into the RTC chip on ODROID-C2 use the following command: <code>odroid@odroid:~$ sudo hwclock -w </code> Verify the date has been saved onto the RTC on ODROID-C2 with: <code>odroid@odroid:~$ sudo hwclock -r</code>

<WRAP  left round important 100%>
** Kernel update will break the RTC functionality **\\
To avoid this problem, you can use this workaround that will patch the dtb all the time \\
<code>sudo -s
echo '#!/bin/sh' > /etc/kernel/postinst.d/rtc
echp 'fdtput -t s /boot/meson64_odroidc2.dtb /i2c@c1108500/pcf8563@51 status "okay"' >> /etc/kernel/postinst.d/rtc
chmod +x /etc/kernel/postinst.d/rtc</code>

</WRAP> \\
==== Android ====
<note tip>
This guide works on Android 5.1.1 V2.8 and higher version and Android 6.0.1 .
</note>

Open File Manager app.

Edit /storage/internal/boot.ini like this. (near end of file).

Before edit.
<code>
movi read dtb 0 ${dtbaddr}
# load kernel from vat or boot partition.
movi read boot 0 ${loadaddr}
#fatload mmc 0:1 ${loadaddr} Image_android
booti ${loadaddr} - ${dtbaddr}
</code>

After edit.
<code>
movi read dtb 0 ${dtbaddr}
# load kernel from vat or boot partition.
#movi read boot 0 ${loadaddr}
fatload mmc 0:1 ${loadaddr} Image_android
booti ${loadaddr} - ${dtbaddr}
</code>

Load kernel image from vfat partition built rtc module.

If you could not find 'fatload' command, remove /storage/internal/boot.ini file and reboot system.
===== Don't use NTP service =====
<WRAP  left round important 100%>
**Update**\\
If your network firewall is blocking the ntp service or no internet connection, you must stop the ntp service. Once the NTP failed, the RTC value could be reset !!! \\
</WRAP> \\
**Credit:**\\
This instruction was made by phaseshifter (our forum member). \\
[[http://forum.odroid.com/viewtopic.php?f=139&t=21765|Original Post]] \\
\\
To stop ntpd: <code> sudo /etc/init.d/ntp stop </code> or <code> sudo service ntp stop </code>
To prevent it from starting at boot: <code> sudo update-rc.d -f ntp remove </code>

===== Estimated life cycle of the battery =====
We cleanly installed Android 5.1 V3.3 image and measured the power consumption.\\
When C2 turns on, it consumes less than 1uA.\\
When C2 turns off, it consumes around 15uA.\\

According to CR2032 Panasonic datasheet, its nominal capacity is 225mAh.\\
[[http://www.cr2032.co/cms/prodimages/panasonic_cr2032_datasheet.pdf]]\\
So its backup time could be around 15000 hours (~ two years).\\
If on/off ratio is 1:1, it can be 3~4 years.