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Pi4J :: Java I/O Library for Raspberry Pi :: Device :: Mcp23017

This repository is a first device specific support project for the MCP23017

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/20001952c.pdf MCP23017/MCP23S17 16-Bit I/O Expander with Serial Interface

Java classes to access the MCP23017 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 MCp23017 interrupt capability. To view/use code that confogures and uses the chip interrupt, see-- com/pi4j/devices/mcp23xxxApplication/Mcp23017PinMonitor

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. ./mvnw clean package
2. cd target/distribution
3. Execute command to set configuration data  (will not be used by example)
4. Execute command to reset Mcp23017
5. Execute command to perform desired MCP23017 operation

ependent upon the -f parameter value logging details will be stored in /tmp/logs/com.pi4j.devices.mcp23017.Mcp23017.log

BCM gpio12 configured as output connected MCP23017 pin 4 spdip25

BCM gpio18 configured as output connected MCP23017 pin 15 spdip8

BCM gpio5 configured as output connected MCP23017 (bar) RESET spdip18

BCM gpio23 configured as input connected MCP23017 INTA spdip20

BCM gpio21 configured as input connected MCP23017 INTB spdip19

BCM gpio22 configured as output connected to LED

Red LED (+) connected to pin0 spdip21 Green LED (+) connected to pin9 spdip2 Yellow LED (+) connected to pin14 spdip7

MCP23008 on TCA9548 switch bus 1 address 0x22

All address pins (A0 A2) are strapped to ground, (A1) strapped to 3.3 V for the chip address 0x22

  • Pi BCM I2C bus 1 - _______________ _______________________ | | | || | | | | || | | | | || | |
    | | || | | | | || | |____________ | | || |> RESET > - MCP23017 0x22 - | | ||< INTA < _____________________ | | |___________ < INTB < | | | | | | |> Drive GPIO > | | 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 MCP23017 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -r 4 -z "{{'gpio23':{'name':'InterruptADetect','dir':'in','pull':'up'}},{' gpio21':{'name':'InterruptBDdetect','dir':'in','pull':'up'}},{'gpio5':{'name':'ResetChip','dir':'out,'int_ena':'no',' initial':'high'}}}" -m "{{'pin0':{'dir':'out','int_ena':'no'}},{'pin14':{'dir':'out','int_ena':'no'}},{'pin4': {'dir':'in','pull':'up','default':'1','do_compare':'yes','int_ena':'yes','act':'low'}},{'pin15':{'dir':'in','pull':' up','default':'1','do_compare':'yes','int_ena':'yes','act':'low'}},{'pin5':{'dir':'out','int_ena':'no'}},{'pin6': {'dir':'out','int_ena':'no'}},{'pin7':{'dir':'out','int_ena':'no'}}}" -x 5 -f 1

  3. Drive pin0 hi low. Drives Red LED.

sudo ./runMcp23017.sh -b 0x01 -a 0x20 -d 0 -o ON -m "{{'pin0':{'dir':'out','int_ena':'no'}}}" -f 1 sudo ./runMcp23017.sh -b 0x01 -a 0x20 -d 0 -o OFF -f 1

  1. Drive pin14 hi low. Drives Yellow LED.

sudo ./runMcp23017.sh -b 0x01 -a 0x22 -d 14 -o ON -m "{{'pin14':{'dir':'out','int_ena':'no'}}}" -f 1 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -d 14 -o OFF -f 1

  1. Read pin4 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -r 4 -z "{{'gpio23':{'name':'InterruptADdetect','dir':'in','pull':'up'}},{' gpio21':{'name':'InterruptBDetect','dir':'in','pull':'up'}},{'gpio5':{'name':'ResetChip','dir':'out,'int_ena':'no',' initial':'high'}}}" -m "{{'pin0':{'dir':'out','int_ena':'no'}},{'pin14':{'dir':'out','int_ena':'no'}},{'pin4': {'dir':'in','pull':'up','default':'0','do_compare':'no','int_ena':'yes','act':'low'}},{'pin15':{'dir':'in','pull':' up','default':'0','do_compare':'no','int_ena':'yes','act':'low'}},{'pin14':{'dir':'out','int_ena':'no'}},{'pin5': {'dir':'out','int_ena':'no'}},{'pin6':{'dir':'out','int_ena':'no'}},{'pin7':{'dir':'out','int_ena':'no'}}}" -x 5 -f 1 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -r 4 -f 1

In separate terminal, alter pin4 python3 import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(12, GPIO.OUT) GPIO.output(12,GPIO.LOW) GPIO.output( 12 , GPIO.HIGH)

  1. Read pin 15 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -r 15 -z "{{'gpio23':{'name':'InterruptADetect','dir':'in','pull':'up'}},{' gpio21':{'name':'InterruptBDetect','dir':'in','pull':'up'}},{'gpio5':{'name':'ResetChip','dir':'out,'int_ena':'no',' initial':'high'}}}" -m "{{'pin0':{'dir':'out','int_ena':'no'}},{'pin14':{'dir':'out','int_ena':'no'}},{'pin4': {'dir':'in','pull':'up','default':'0','do_compare':'no','int_ena':'yes','act':'low'}},{'pin15':{'dir':'in','pull':' up','default':'0','do_compare':'no','int_ena':'yes','act':'low'}},{'pin14':{'dir':'out','int_ena':'no'}},{'pin5': {'dir':'out','int_ena':'no'}},{'pin6':{'dir':'out','int_ena':'no'}},{'pin7':{'dir':'out','int_ena':'no'}}}" -x 5 -f 1 sudo ./runMcp23017.sh -b 0x01 -a 0x22 -r 15 -f 1

In separate terminal, alter pin15 python3 import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(18, GPIO.OUT) GPIO.output(18,GPIO.LOW) GPIO.output( 18 , GPIO.HIGH)