DRAM Clock Adjustment

1. Brief DDR spec. of ODROID-C2 and available DDR clock sets

The DDR parts of C2 support max DDR3-1866 (CL - tRCD - tRP : 13-13-13) and the limit of max DDR clock is 933MHz based on DDR part spec.
Existing DDR clock and timing : 912MHz (912×2=1824) / 13-13-13

Here are the available DDR clock sets you can test:

DDR Clock	CL - tRCD - tRP
1104 MHz	14-14-14
912 MHz	13-13-13
792 MHz	11-11-11
408 MHz	7-7-7

Max ddr clock based on DDR parts of C2 is 933MHz.

So, when you run the DDR clock at 1104MHz, system stability can be unstable depending on ddr parts of each board, because of its over-clocking value, so 1104MHz is not guaranteed for system stability.

2. Update Guide (1) for Ubuntu

This section is for Ubuntu. First, download c2_update_ddrclk.sh to your root filesystem.

$ wget https://dn.odroid.com/S905/BootLoader/ODROID-C2/c2_update_ddrclk.sh
$ chmod +x ./c2_update_ddrclk.sh

The usage of c2_update_ddrclk.sh is as follows:

Usage : ./c2_update_ddrclk.sh  < DDR_CLK (1104 | 912 | 792 | 408) >

After updating, you must run reboot the system.

$ ./c2_update_ddrclk.sh 1104
$ reboot

c2_update_ddrclk.sh

Here is c2_update_ddrclk.sh.

c2_update_ddrclk.sh

#!/bin/sh
#
# Copyright (C) 2016 Hardkernel Co,. Ltd
# Joy Cho <joy.cho@hardkernel.com>
#
# SPDX-License-Identifier:      GPL-2.0+
#
# update ddr clock for Ubuntu
#
 
if [ -z $1 ]; then
        echo "Usage ./c2_update_ddrclk.sh <DDR_CLK (1104 | 912 | 792 | 408)>"
        exit 1
fi
 
if [ $1 != 1104 -a $1 != 912 -a $1 != 792 -a $1 != 408 ]; then
        echo "Wrong DDRCLK! Usage ./c2_update_ddrclk.sh <DDR_CLK (1104 | 912 | 792 | 408)>"
        exit 1
fi
 
DDRCLK=$1
 
bl1=/tmp/bl1.bin.hardkernel.$DDRCLK
tmp=/tmp/temp.bin
 
##### 1. check the current DDR clock ####
dd if=/dev/mmcblk0 of=$tmp bs=1 count=2 skip=43530 status=none
CUR_DDRCLK=$(hexdump -e '"%d"' $tmp)
 
if [ $DDRCLK -eq $CUR_DDRCLK ]; then
        echo "current ddr clk is already set as $DDRCLK MHz"
        exit 1
fi
 
echo "existing DDR clk is $CUR_DDRCLK"
 
##### 2. download bl1 binary from dn server ####
wget -P /tmp/ https://dn.odroid.com/S905/BootLoader/ODROID-C2/bl1.bin.hardkernel.$DDRCLK
if [ ! -f $bl1 ];then
        echo "error: bl1 binary doesn't exist"
        exit 1
fi
 
dd if=$bl1 of=/dev/mmcblk0 bs=1 count=442 status=none
dd if=$bl1 of=/dev/mmcblk0 bs=512 skip=1 seek=1 status=none
 
echo "Update done!"
 
##### 3. check the updated DDR clock ####
echo "Now let's check if update has been completed..."
 
dd if=/dev/mmcblk0 of=$tmp bs=1 count=2 skip=43530 status=none
 
CUR_DDRCLK=$(hexdump -e '"%d"' $tmp)
echo "updated DDR clk is $CUR_DDRCLK"
 
if [ $DDRCLK != $CUR_DDRCLK ]; then
	echo "updating DDR clock FAIL!! Expected : $DDRCLK, Updated : $CUR_DDRCLK"
else
	echo "updating DDR clock has been completed!!!"
fi
 
rm $bl1
rm $tmp

3. Update Guide (2) for Android

This section is for Android.

Run Browser

open https://dn.odroid.com/S905/BootLoader/ODROID-C2/

Download files

updatepackage-odroidc2-ddr-408[792/912/1104].zip

Run ODROID Utility app

Click menu and Select “Package install from storage”

Select "File Manager"

Open “Download” folder.

Select updatepackage-odroidc2-ddr-xxx.zip wanted DDR clock

Process "recovery"

4. How to confirm bl1 boot with the new DDR clock has been updated well

Wht the output message while updating with c2_update_ddrclk.sh, you can confirm if update is done with the new DDR clock you choose as following.

$ ./c2_update_ddrclk.sh  1104
 
existing DDR clk is 912   <<<------
.....
.....
Update done!
Now let's check if update has been completed...
updated DDR clk is 1104 <<<------
updating DDR clock has been completed!!!

After reboot, you can check the DDR configuration using the following logs of boot loader if you have a usb-uart module kit.

BL2 Built : 11:44:26, Nov 25 2015. 
Board ID = 8
set vcck to 1100 mv
set vddee to 1070 mv
CPU clk: 1536MHz
DDR channel setting: DDR0 Rank0+1 same
DDR0: 2048MB(auto) @ 912MHz(2T)-13