mirror of
https://github.com/openhab/openhab-addons.git
synced 2025-01-10 15:11:59 +01:00
100 lines
4.4 KiB
Markdown
100 lines
4.4 KiB
Markdown
# MCP23017 Binding
|
|
|
|
This binding allows you to have native access for MCP23017 I/O expander on I2C bus.
|
|
It was tested with Raspberry Pi 2 and Raspberry Pi 3, but probably should work with other devices supported by [Pi4J](https://pi4j.com/) library.
|
|
|
|
On Raspberry Pi the user on which openHAB is running (default user name is "openhab") needs to be added to groups "i2c" and "gpio".
|
|
As the MCP23017 has 3 address pins, you are restricted to 8 devices on an I2C bus.
|
|
To use more devices you have to open further I2C busses.
|
|
Therefore you can use overlays to enable bit banging I2C busses on the Raspberry Pi connector, up to I2C6.
|
|
<https://github.com/raspberrypi/firmware/tree/master/boot/overlays>
|
|
|
|
## Dependencies
|
|
|
|
Make sure that the [wiringPi](http://wiringpi.com/) library has been installed and that the `gpio` command line tool is available to openHAB.
|
|
The shared library `libwiringPi.so` is required by the [Pi4J](https://pi4j.com/) Java library to access the GPIO ports.
|
|
Without satisfying this dependency you will see strange `NoClassDefFoundError: Could not initialize class ...` errors in the openHAB logs.
|
|
|
|
## Supported Things
|
|
|
|
This binding supports one thing type:
|
|
|
|
mcp23017 - which is a mcp23017 chip connected to an I2C bus on specified HEX address and bus number
|
|
|
|
## Thing Configuration
|
|
|
|
- Required configuration for mcp23017 thing:
|
|
|
|
| Parameter | Description | Default value |
|
|
|------------|-----------------------------------------------------------------------------------------------------------------------------------|---------------|
|
|
| address | MCP23017 I2C bus address. On Raspberry Pi it can be checked as a result of command: "i2cdetect -y 1". Value should be set in HEX. | "20" |
|
|
| bus_number | a bus number to which mcp23017 is connected. On RPI2 and RPI3 it will be "1", on RPI1 it will be "0". | "1" |
|
|
|
|
## Channels
|
|
|
|
mcp23017 supports 16 channels in 2 groups:
|
|
|
|
| Group | Channels | Additional parameters |
|
|
|--------|----------------------------------------------------------------|-------------------------------------------|
|
|
| input | A0, A1, A2, A3, A4, A5, A6, A7, B0, B1, B2, B3, B4, B5, B6, B7 | pull_mode (OFF, PULL_UP), default is OFF |
|
|
| output | A0, A1, A2, A3, A4, A5, A6, A7, B0, B1, B2, B3, B4, B5, B6, B7 | default_state (LOW, HIGH), default is LOW |
|
|
|
|
Channel determines MCP23017 PIN we want to use.
|
|
|
|
Group determines mode in which PIN shoud work.
|
|
|
|
When PIN should work as DIGITAL_INPUT, channel from group "input" should be used.
|
|
|
|
When PIN should work as DIGITAL_OUTPUT, channel from group "output" should be used.
|
|
|
|
## Full Example
|
|
|
|
Let's imagine a setup with:
|
|
|
|
1. a wall switch connected to pin B1 on the MCP23017 chip which should turn on/off your LED light when pressed (released).
|
|
1. a relay which is connected to pin A0 on the MCP23017 chip. This relay takes care of turning on/off your light.
|
|
|
|
Pressing (and releasing) a wall switch should notify openHAB, and then openHAB should change state of relay to on/off the light.
|
|
Your pin B1 should work as DIGITAL_INPUT, because it READS state of a PIN (state of wall switch). Your pin A0 should work as DIGITAL_OUTPUT
|
|
because openHAB will SET state of this PIN. So your config should look like this:
|
|
|
|
- Things:
|
|
|
|
Minimal configuration:
|
|
|
|
```java
|
|
Thing mcp23017:mcp23017:chipA "MCP23017 chip A" [address=20,bus=1]
|
|
```
|
|
|
|
Configuration with default_state and pull_mode:
|
|
|
|
```java
|
|
Thing mcp23017:mcp23017:chipA "MCP23017 chip A" [address=20,bus=1] {
|
|
Type output_pin : output#A0 [default_state="HIGH"]
|
|
Type output_pin : output#A1 [default_state="LOW"]
|
|
Type output_pin : output#A2 [active_low="y"]
|
|
Type output_pin : output#A2 [default_state="LOW", active_low="y"]
|
|
|
|
Type input_pin : input#B0 [pull_mode="PULL_UP"]
|
|
Type input_pin : input#B1 [pull_mode="OFF"]
|
|
}
|
|
```
|
|
|
|
- Items:
|
|
|
|
```java
|
|
Switch living_room_led_switch "Living room LED switch" {channel="mcp23017:mcp23017:chipA:output#A0"}
|
|
Contact living_room_led_contact "Living room LED contact" {channel="mcp23017:mcp23017:chipA:input#B1"}
|
|
```
|
|
|
|
- Rules:
|
|
|
|
```java
|
|
rule "living_room_led contact"
|
|
when
|
|
Item living_room_led_contact changed to OPEN
|
|
then
|
|
living_room_led_switch.sendCommand(if(living_room_led_switch.state != ON) ON else OFF)
|
|
end
|
|
```
|