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en:c_hardware_i2c [2016/03/30 10:25] john1117 created |
en:c_hardware_i2c [2017/06/20 13:18] (current) brian.kim [How to change the I2C clock speed] |
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| ====== I2C ====== | ====== I2C ====== | ||
| - | This page introduces how you can interface your I2C devices to **ODROID-C**. | + | This page introduces how you can interface your I2C devices to **ODROID-C** series. |
| ===== H/W connection ===== | ===== H/W connection ===== | ||
| Line 19: | Line 19: | ||
| $ modprobe aml_i2c | $ modprobe aml_i2c | ||
| </code> | </code> | ||
| - | If you have to load the driver every time whenever your **ODROID-C1** starts, simply you can register the driver into **/etc/modules**. | + | If you have to load the driver every time whenever your **ODROID-C** starts, simply you can register the driver into **/etc/modules**. |
| <code> | <code> | ||
| - | $ sudo echo "aml_i2c" >> /etc/modules | + | $ echo "aml_i2c" | sudo tee /etc/modules |
| </code> | </code> | ||
| This adds one line at end of the file, /etc/modules, and load the driver on boot automatically. | This adds one line at end of the file, /etc/modules, and load the driver on boot automatically. | ||
| + | |||
| + | |||
| + | ===== How to change the I2C clock speed ===== | ||
| + | To change the I2C clock speed, you need to modify the DT(Device Tree) file.\\ | ||
| + | |||
| + | Install required packages. | ||
| + | <code> | ||
| + | sudo apt-get install device-tree-compiler i2c-tools | ||
| + | </code> | ||
| + | |||
| + | Make a backup of DTB file. | ||
| + | <code> | ||
| + | cp /media/boot/meson64_odroidc2.dtb /media/boot/meson64_odroidc2.dtb.org | ||
| + | </code> | ||
| + | |||
| + | Change the DTB file for i2c-1 (i2c channel #1) | ||
| + | <code> | ||
| + | fdtput -t i /media/boot/meson64_odroidc2.dtb /i2c@c1108500 master_i2c_speed "100000" | ||
| + | sync | ||
| + | reboot | ||
| + | </code> | ||
| + | |||
| + | Change the DTB file for i2c-2 (i2c channel #2) | ||
| + | <code> | ||
| + | fdtput -t i /media/boot/meson64_odroidc2.dtb /i2c@c11087c0 master_i2c_speed "100000" | ||
| + | sync | ||
| + | reboot | ||
| + | </code> | ||
| + | |||
| + | If you want to go back to original 300Khz mode, change "100000" to "300000".\\ | ||
| + | |||
| + | **Actual I2C clock speed** (Measured with an oscilloscope)\\ | ||
| + | In 300Khz mode : 270Khz \\ | ||
| + | In 100Khz mode : 80Khz \\ | ||
| + | |||
| + | **Default I2C clock speed** \\ | ||
| + | C1/C1+/C0 : 100Khz mode \\ | ||
| + | C2 : 400Khz mode \\ | ||
| + | |||
| ===== Tutorials ===== | ===== Tutorials ===== | ||
| [[wb_c_16x2lcd|{{:en:weather_board:weatherboard16x2.jpg?150|}}]] [[wb_c|{{:en:weather_board:wb_odroidc5.png?135|}}]] | [[wb_c_16x2lcd|{{:en:weather_board:weatherboard16x2.jpg?150|}}]] [[wb_c|{{:en:weather_board:wb_odroidc5.png?135|}}]] | ||
| * [[ wb_c_16x2lcd | WEATHER-BOARD with 16x2 LCD on ODROID-C ]] | * [[ wb_c_16x2lcd | WEATHER-BOARD with 16x2 LCD on ODROID-C ]] | ||
| * [[ wb_c | WEATHER-BOARD on ODROID-C ]] | * [[ wb_c | WEATHER-BOARD on ODROID-C ]] | ||
