Usage GPIO with I2C I/O expander
There is no GPIO on external I/O port of ODROID-H3. But, You can use GPIO with I2C I/O expander.
| 16 Port I2C GPIO Board Header Pin | |
| VCC | Power Supply Input (1.8V ~ 5.0V) |
| GND | Ground |
| SCL | I2C Serial Clock Input |
| SDA | I2C Serial Data Input/Output |
| RST | MCP23017 Reset (Active Low) |
| ITA | Interrupt Output for Port A (PA0 ~ PA7), Output Configurable |
| ITB | Interrupt Output for Port B (PB0 ~ PB7), Output Configurable |
| I2C Address configuration | |||
| A0 | A1 | A2 | I2C Address |
| GND | GND | GND | 0x20 (Default) |
| GND | GND | VCC | 0x22 |
| GND | VCC | GND | 0x24 |
| GND | VCC | VCC | 0x26 |
| VCC | GND | GND | 0x28 |
| VCC | GND | VCC | 0x2A |
| VCC | VCC | GND | 0x2C |
| VCC | VCC | VCC | 0x2D |
An LED example with MCP23017 I2C GPIO expander
Wiring
We're going to make an LED example with the GPIO expander(MCP23017 Datasheet).
H2+
H2
Download fritzing
- MCP23017 board part ☞ i2c_io_expander.fzpz
- ODROID-H2+ part ☞ odroid-h2plus.fzpz
- ODROID-H2 part ☞ odroid-h2.fzpz
- fritzing parts(H2) ☞ i2c_io_expander.fzz
- fritzing parts(H2+) ☞ h2plus_i2c_io_expander.fzz
Connection Check
If you have done the wiring well, you can see the device as the following commands.
sudo apt install i2c-tools
- If you're using an older kernel than 4.18, tap the “Old kernel version”.
kernel 4.18 or higher
When you have wired the GPIO expander to Pin #18(SCL) and #20(SDA).
sudo i2cdetect -y -r 2
When you have wired the GPIO expander to Pin #13(SCL) and #15(SDA).
sudo i2cdetect -y -r 3
Old kernel version
When you have wired the GPIO expander to Pin #18(SCL) and #20(SDA).
sudo i2cdetect -y -r 5
When you have wired the GPIO expander to Pin #13(SCL) and #15(SDA).
sudo i2cdetect -y -r 6
Install & build python packages
sudo apt install git python3-dev libi2c-dev python3-smbus
If you got this error.
E: Unable to locate package python3-smbus
Build the python3-smbus package.
git clone https://github.com/tkurbad/python3-smbus.git cd python3-smbus python3 setup.py build python3 setup.py install
Get source code
git clone https://github.com/hardkernel/16port_i2c_gpio.git
Run led_example
chmod +x mcp23017.py
./mcp23017.py -h odroid@odroid:~/work/mcp23017_python$ ./mcp23017.py -h Usage: mcp23017.py I2CBUS blink mcp23017.py I2CBUS -w GPIO [1|0] mcp23017.py I2CBUS -r GPIO Options: -h, --help show this help message and exit -w, --write Write HIGH or LOW to GPIO -r, --read Read from GPIO -a, --all All off or on
- If you're using an older kernel than 4.18, tap the “Old kernel version”.
kernel 4.18 or higher
When you have wired the GPIO expander to Pin #18(SCL) and #20(SDA).
sudo ./mcp23017.py 2 blink sudo ./mcp23017.py 2 -w 0 1 sudo ./mcp23017.py 2 -r 5
When you have wired the I/O expander to Pin #13(SCL) and #15(SDA).
sudo ./mcp23017.py 3 blink sudo ./mcp23017.py 3 -w 0 1 sudo ./mcp23017.py 3 -r 5
Old kernel version
When you have wired the GPIO expander to Pin #18(SCL) and #20(SDA).
sudo ./mcp23017.py 5 blink sudo ./mcp23017.py 5 -w 0 1 sudo ./mcp23017.py 5 -r 5
When you have wired the I/O expander to Pin #13(SCL) and #15(SDA).
sudo ./mcp23017.py 6 blink sudo ./mcp23017.py 6 -w 0 1 sudo ./mcp23017.py 6 -r 5
Changing the I2C speed
GPIO toggle frequency on mcp23017
1MHz I2C Speed
400kHz I2C Speed
100kHz I2C Speed
GPIO output current
Output Low : 8.0mA
Output High : 3.0 mA
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