https://github.com/keriszafir/mcp23017-demo
Demonstration programs for controlling MCP23017 I/O expanders
https://github.com/keriszafir/mcp23017-demo
Last synced: 3 months ago
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Demonstration programs for controlling MCP23017 I/O expanders
- Host: GitHub
- URL: https://github.com/keriszafir/mcp23017-demo
- Owner: keriszafir
- License: gpl-3.0
- Created: 2015-02-12T18:26:17.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2015-02-15T16:34:28.000Z (over 10 years ago)
- Last Synced: 2025-01-22T07:33:55.842Z (4 months ago)
- Language: C
- Size: 215 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# mcp23017-demo
Demonstration programs for controlling MCP23017 I/O expanders
These programs will help you understand how to control MCP23017 expanders
(most notably, setting them up as outputs).
You must have the libi2c-dev installed.
Normally, Linux security policy prohibits direct access to hardware for non-root users.
You can change it by creating a file by creating a udev rule file:
```
sudo nano /etc/udev/rules.d/60-i2c-tools.rules
```
with contents as following:
```
KERNEL=="i2c-[1-9]*", GROUP="i2c", MODE="0660"
```
This will allow anyone from i2c group to write to /dev/i2c-*.
You will have to add your user account to the i2c group:
```
sudo adduser [username] i2c
```
The udev rule file is included for convenience, you can copy it into /etc/udev/rules.d
It's best to compile and run this on a Raspberry Pi mod B revision 2, or newer.
A+, B+ and RPi 2 will work too.
Any Linux distribution should work, although Raspbian wheezy is the most popular
and you want to stick with this.