Skip to content

Latest commit

 

History

History
138 lines (86 loc) · 5.35 KB

README.md

File metadata and controls

138 lines (86 loc) · 5.35 KB
Raw

Pi4J :: Java I/O Library for Raspberry Pi :: Device :: Mcp23008

This repository is a first device specific support project for the MCP23008

This is an example implementation and will need to be adjusted to fit your needs.

Project by Tom Aarts

==========================================================================

https://ww1.microchip.com/downloads/en/DeviceDoc/21919e.pdf MCP23008/MCP23S08 8-Bit I/O Expander with Serial Interface

Java classes to access the MCP23008 GPIO controller as an application.

Supported functions. 1. reset chip 2. Configure any/all pins (all configurations options) 3. Supports logging facilities implemented by log4_v2

Example does not use the MCp23008 interrupt capability. 
To view/use code that confogures and uses the chip interrupt,
 see-- com/pi4j/devices/mcp23xxxApplication/Mcp23008PinMonitor

The classes are implemented using the Pi4j_V2 requirements of September 1 2020.

The project uses one addition pom requirement of log4j version 2. The project uses the required slf4j basic logging and this Log4j version 2 to support logging to a file.

Update local repository with this SHA1 id. In the projects base directory execute the following. Note: this project is not listed in the parent pom file, therefore mvn (maven) commands in the parent path will not read this pom file.

Program options -q 9548#1 -r 3 -p pin0 -c 23008#1 -z 'pi GPIOs' -m 'MCP23xxx pin configuration' -q first chip in the i2c circuit. In the example this is a TCA9548 mux, If the 23008 chip was the directly on the Pi bus, the the value would be -q 23008#1 -r read this MCP23xxx pin -d drive this MCP23xxx pin based on -o ON or OFF -z Pi gpio configuration -m MCP23xxx pin configuration

1. mvn clean package
2. cd target/distribution
3. Execute command to set configuration data  (will not be used by example)
4. Execute command to reset Mcp23008
5. Execute command to perform desired MCP23008 operation

ependent upon the -f parameter value logging details will be stored in /tmp/logs/com.pi4j.devices.mcp23008.Mcp23008.log

BCM gpio16 configured as output connected MCP23008 pin 4 pdip14

BCM gpio13 configured as output connected MCP23008 (bar) RESET pdip6

BCM gpio27 configured as input connected MCP23008 INT pdip8

BCM gpio22 configured as output connected to LED

Red LED (+) connected to pin0 pdip10 Green LED (+) connected to pin1 pdip11 Yellow LED (+) connected to pin2 pdip12

MCP23008 on Pi BCM 1 address 0x20 All address pins (A0 A1 A2) are strapped to ground for the chips default address 0x20

  • Pi BCM I2C bus 1 - ______________ _______________________ | | | | | | | | | | | | |
    | | | | | | | ____________________ | | |> RESET > - MCP23008 0x20 - | | ____________________ | |______ < INT < | | | | | | LEDs |__________________> Drive GPIO >|

NOTE !!!!! Using the $@ in the module call alows variable number of arguments. But, agruments wrapped by " " cannot contain spaces. So as you can see the -m and -z values wrapped by " " contain no spaces..

  1. Set pin and chip configuration property files sudo ./runAppPropertySet.sh sudo ./runAppPropertyRead.sh

  2. Reset MCP23008 sudo ./runMcp23008.sh -b 0x1 -a 0x20 -r 3 -z "{{'gpio27':{'name':'InterruptDetect','dir':'in','pull':'up'}},{'gpio13':{'name':'ResetChip','dir':'out','int_ena':'no','initial':'high'}}}" -m "{{'pin0':{'dir':'out','int_ena':'no'}},{'pin1':{'dir':'out','int_ena':'no'}},{'pin2':{'dir':'out','int_ena':'no'}},{'pin3':{'dir':'in','pull':'up','default':'1','do_compare':'yes','int_ena':'yes','act':'low'}},{'pin4':{'dir':'out','int_ena':'no'}},{'pin5':{'dir':'out','int_ena':'no'}},{'pin6':{'dir':'out','int_ena':'no'}},{'pin7':{'dir':'out','int_ena':'no'}}}" -x 13 -f 1

  3. Configure pins of MCP23008, do reset first

All pins sudo ./runMcp23008.sh -b 0x1 -a 0x20 -r 3 -z "{{'gpio27':{'name':'InterruptDetect','dir':'in','pull':'up'}},{'gpio13':{'name':'ResetChip','dir':'out','int_ena':'no','initial':'high'}}}" -m "{{'pin0':{'dir':'out','int_ena':'no'}},{'pin1':{'dir':'out','int_ena':'no'}},{'pin2':{'dir':'out','int_ena':'no'}},{'pin3':{'dir':'in','pull':'up','default':'1','do_compare':'yes','int_ena':'yes','act':'low'}},{'pin4':{'dir':'out','int_ena':'no'}},{'pin5':{'dir':'out','int_ena':'no'}},{'pin6':{'dir':'out','int_ena':'no'}},{'pin7':{'dir':'out','int_ena':'no'}}}" -x 13 -f 1

  1. Drive MCP23008 pin0 Red Led hi low sudo ./runMcp23008.sh -b 0x1 -a 0x20 -d 0 -o ON -m "{{'pin0':{'dir':'out','int_ena':'no'}}}" -f 1 sudo ./runMcp23008.sh -b 0x1 -a 0x20 -d 0 -o OFF -f 1

  2. Read MCP23008 pin4 Read 4 sudo ./runMcp23008.sh -b 0x1 -a 0x20 -r 4 -m "{{'pin4':{'dir':'in','pull':'down'}}}" -f 1 This will set pin4 high or low python3 import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(16, GPIO.OUT) GPIO.output(16,GPIO.LOW) GPIO.output( 16 , GPIO.HIGH)