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update version of i2c dependency in package.json, added feature for p…
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…ullup

resistors on gpio
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@askanhesse
askanhesse committed Sep 26, 2018
1 parent 24217ed commit 0be64b9
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3 changes: 3 additions & 0 deletions .gitignore
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Expand Up @@ -23,3 +23,6 @@ build/Release
# Deployed apps should consider commenting this line out:
# see https://npmjs.org/doc/faq.html#Should-I-check-my-node_modules-folder-into-git
node_modules

# Intellij
.idea/
4 changes: 2 additions & 2 deletions README.md
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Expand Up @@ -3,7 +3,7 @@ node-mcp23017

Node.js library for the I2C I/O Expander MCP23017 on a Raspberry Pi

It currently only supports reading from and writing to the chip
It currently supports reading, writing and changing the pull-up resistor of the GPIOs.

The module tries to mimic the Arduino-Syntax

Expand Down Expand Up @@ -79,6 +79,7 @@ var mcp = new MCP23017({
for (var i = 0; i < 16; i++) {
mcp.pinMode(i, mcp.OUTPUT);
//mcp.pinMode(i, mcp.INPUT); //if you want them to be inputs
//mcp.pinMode(i, mcp.INPUT_PULLUP); //if you want them to be pullup inputs
}

mcp.digitalWrite(0, mcp.HIGH); //set GPIO A Pin 0 to state HIGH
Expand Down Expand Up @@ -140,7 +141,6 @@ setInterval(blink, 100); //blink all LED's with a delay of 100ms
## TODO
- implement built-in pullup resistors
- implement interrupt handling
## Acknowledgement
Expand Down
7 changes: 3 additions & 4 deletions examples/package.json
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@@ -1,8 +1,7 @@
{
"name": "mcp23017-blink-example",
"version": "1.0.0",
"description": "blinks 16 leds",
"main": "blink.js",
"name": "mcp23017-examples",
"version": "1.1.0",
"description": "different examples for showing functionality of library.",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1"
},
Expand Down
38 changes: 38 additions & 0 deletions examples/pull_down.js
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@@ -0,0 +1,38 @@
var MCP23017 = require('node-mcp23017');

var mcp = new MCP23017({
address: 0x20, //all address pins pulled low
device: '/dev/i2c-1', // Model B
debug: false
});

mcp.pinMode(0, mcp.INPUT_PULLUP);
mcp.pinMode(1, mcp.INPUT_PULLUP);
mcp.pinMode(2, mcp.INPUT_PULLUP);
mcp.pinMode(3, mcp.INPUT_PULLUP);
mcp.pinMode(4, mcp.INPUT_PULLUP);
mcp.pinMode(5, mcp.INPUT_PULLUP);
mcp.pinMode(6, mcp.INPUT_PULLUP);
mcp.pinMode(7, mcp.INPUT_PULLUP);
mcp.pinMode(8, mcp.INPUT_PULLUP);
mcp.pinMode(9, mcp.INPUT_PULLUP);
mcp.pinMode(10, mcp.INPUT_PULLUP);
mcp.pinMode(11, mcp.INPUT_PULLUP);
mcp.pinMode(12, mcp.INPUT_PULLUP);
mcp.pinMode(13, mcp.INPUT_PULLUP);
mcp.pinMode(14, mcp.INPUT_PULLUP);
mcp.pinMode(15, mcp.INPUT); // this one should float from time to time

setInterval(function(){

var test = function(i){
return function(err, value){
if(value == false){
console.log("Pull down on pin " + i, value);
}
}
}

for (var i = 8; i < 16; i++) {
mcp.digitalRead(i, test(i));
}
139 changes: 86 additions & 53 deletions lib/mcp23017.js
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@@ -1,24 +1,30 @@
var DIRECTION_GPIOA = 0x00,
DIRECTION_GPIOB = 0x01,
FROM_GPIOA = 0x12,
FROM_GPIOB = 0x13,
TO_GPIOA = 0x14,
TO_GPIOB = 0x15,
var REGISTER_GPIOA = 0x00,
REGISTER_GPIOB = 0x01,
REGISTER_GPIOA_PULLUP = 0x0C;
REGISTER_GPIOB_PULLUP = 0x0D;
READ_GPIOA_ADDR = 0x12,
READ_GPIOB_ADDR = 0x13,
WRITE_GPIOA_ADDR = 0x14,
WRITE_GPIOB_ADDR = 0x15,
Wire = require('i2c');

var MCP23017 = (function() {
MCP23017.prototype.HIGH = 1;
MCP23017.prototype.LOW = 0;
MCP23017.prototype.INPUT_PULLUP = 2;
MCP23017.prototype.INPUT = 1;
MCP23017.prototype.OUTPUT = 0;

MCP23017.prototype.address = 0x20; //if the mcp has all adress lines pulled low

MCP23017.prototype.oldADir = 0xff; //initial state of GPIO A
MCP23017.prototype.oldBDir = 0xff; //initial state of GPIO A
MCP23017.prototype.dirAState = 0xff; //initial state of GPIO A bank
MCP23017.prototype.dirBState = 0xff; //initial state of GPIO B bank

MCP23017.prototype.oldGpioA = 0x0; //initial state of GPIO A
MCP23017.prototype.oldGpioB = 0x0; //initial state of GPIO B
MCP23017.prototype.dirAPullUpState = 0x0; //initial state of GPIO A pull up resistor state
MCP23017.prototype.dirBPullUpState = 0x0; //initial state of GPIO B pull up resistor state

MCP23017.prototype.gpioAState = 0x0; //initial state of GPIOS A
MCP23017.prototype.gpioBState = 0x0; //initial state of GPIOS B

function MCP23017 (config) {
this.address = config.address;
Expand All @@ -34,8 +40,8 @@ var MCP23017 = (function() {

//inits both registers as an input
MCP23017.prototype.reset = function () {
this.oldBDir = 0xff;
this.oldADir = 0xff;
this.dirBState = 0xff;
this.dirAState = 0xff;
this._initGpioA();
this._initGpioB();
};
Expand All @@ -44,7 +50,7 @@ var MCP23017 = (function() {
sets an pin as an INPUT or OUTPUT
*/
MCP23017.prototype.pinMode = function (pin, dir) {
if (dir !== this.INPUT && dir !== this.OUTPUT) {
if (dir !== this.INPUT && dir !== this.INPUT_PULLUP && dir !== this.OUTPUT) {
console.error('invalid value', dir);
return;
}
Expand All @@ -56,87 +62,114 @@ var MCP23017 = (function() {
}

//delegate to funktion that handles low level stuff
this._setGpioDir(pin >= 8 ? pin - 8 : pin, dir, pin >= 8 ? DIRECTION_GPIOB : DIRECTION_GPIOA);
this._setGpioDir(pin >= 8 ? pin - 8 : pin, dir, pin >= 8 ? REGISTER_GPIOB : REGISTER_GPIOA, pin >= 8 ? REGISTER_GPIOB_PULLUP : REGISTER_GPIOA_PULLUP);
};

/*
internally used to set the direction registers
*/
MCP23017.prototype._setGpioDir = function (pin, dir, register) {
MCP23017.prototype._setGpioDir = function (pin, dir, registerDirection, registerPullUp) {
var pinHexMask = Math.pow(2, pin),
registerValue;
registerDir,
registerPullUpDir;

if (register === DIRECTION_GPIOA) {
registerValue = this.oldADir;
if (registerDirection === REGISTER_GPIOA) {
registerDir = this.dirAState;
if (dir === this.OUTPUT) {
if ((this.oldADir & pinHexMask) === pinHexMask) {
if ((this.dirAState & pinHexMask) === pinHexMask) {
this.log('setting pin \'' + pin + '\' as an OUTPUT');
this.oldADir = this.oldADir ^ pinHexMask;
registerValue = this.oldADir;
this.dirAState = this.dirAState ^ pinHexMask;
registerDir = this.dirAState;
} else {
this.log('pin \'' + pin + '\' already an OUTPUT');
}
} else if (dir === this.INPUT) {
if ((this.oldADir & pinHexMask) !== pinHexMask) {
} else if (dir === this.INPUT || dir === this.INPUT_PULLUP) {
if ((this.dirAState & pinHexMask) !== pinHexMask) {
this.log('setting pin \'' + pin + '\' as an INPUT');
this.oldADir = this.oldADir ^ pinHexMask;
registerValue = this.oldADir;
this.dirAState = this.dirAState ^ pinHexMask;
registerDir = this.dirAState;
} else {
this.log('pin \'' + pin + '\' already an INPUT');
}
if (dir === this.INPUT_PULLUP) {
registerPullUpDir = this.dirAPullUpState;
if ((this.dirAPullUpState & pinHexMask) !== pinHexMask) {
this.log('activate INPUT_PULLUP for pin \'' + pin + '\'');
this.dirAPullUpState = this.dirAPullUpState ^ pinHexMask;
registerPullUpDir = this.dirAPullUpState;
} else {
this.log('pin \'' + pin + '\' already activated INPUT_PULLUP');
}
}
}
} else if (register === DIRECTION_GPIOB) {
registerValue = this.oldBDir;
} else if (registerDirection === REGISTER_GPIOB) {
registerDir = this.dirBState;
if (dir === this.OUTPUT) {
if ((this.oldBDir & pinHexMask) === pinHexMask) {
if ((this.dirBState & pinHexMask) === pinHexMask) {
this.log('setting pin \'' + pin + '\' as an OUTPUT');
this.oldBDir = this.oldBDir ^ pinHexMask;
registerValue = this.oldBDir;
this.dirBState = this.dirBState ^ pinHexMask;
registerDir = this.dirBState;
} else {
this.log('pin \'' + pin + '\' already an OUTPUT');
}
} else if (dir === this.INPUT) {
if ((this.oldBDir & pinHexMask) !== pinHexMask) {
} else if (dir === this.INPUT || dir === this.INPUT_PULLUP) {
if ((this.dirBState & pinHexMask) !== pinHexMask) {
this.log('setting pin \'' + pin + '\' as an INPUT');
this.oldBDir = this.oldBDir ^ pinHexMask;
registerValue = this.oldBDir;
this.dirBState = this.dirBState ^ pinHexMask;
registerDir = this.dirBState;
} else {
this.log('pin \'' + pin + '\' already an INPUT');
}
if (dir === this.INPUT_PULLUP) {
registerPullUpDir = this.dirBPullUpState;
if ((this.dirBPullUpState & pinHexMask) !== pinHexMask) {
this.log('activate INPUT_PULLUP for pin \'' + pin + '\'');
this.dirBPullUpState = this.dirBPullUpState ^ pinHexMask;
registerPullUpDir = this.dirBPullUpState;
} else {
this.log('pin \'' + pin + '\' already activated INPUT_PULLUP');
}
}
}
}
this._send(register, [registerValue]);
this.log('register: ' + register + ', value: ' + registerValue);

this._send(register, [registerDir]);
this.log('pin: ' + pin + ', register: ' + register + ', value: ' + registerDir);

if(registerPullUpDir !== undefined){
this._send(registerPullUp, [registerPullUpDir]);
this.log('pin: ' + pin + ', register: ' + registerPullUp + ', pull up value: ' + registerPullUpDir);
}
};

MCP23017.prototype._setGpioAPinValue = function (pin, value) {
var pinHexMask = Math.pow(2, pin);
if (value === 0) {
if ((this.oldGpioA & pinHexMask) === pinHexMask) {
this.oldGpioA = this.oldGpioA ^ pinHexMask;
this._send(TO_GPIOA, [this.oldGpioA]);
if ((this.gpioAState & pinHexMask) === pinHexMask) {
this.gpioAState = this.gpioAState ^ pinHexMask;
this._send(WRITE_GPIOA_ADDR, [this.gpioAState]);
}
}
if (value === 1) {
if ((this.oldGpioA & pinHexMask) !== pinHexMask) {
this.oldGpioA = this.oldGpioA ^ pinHexMask;
this._send(TO_GPIOA, [this.oldGpioA]);
if ((this.gpioAState & pinHexMask) !== pinHexMask) {
this.gpioAState = this.gpioAState ^ pinHexMask;
this._send(WRITE_GPIOA_ADDR, [this.gpioAState]);
}
}
};

MCP23017.prototype._setGpioBPinValue = function (pin, value) {
var pinHexMask = Math.pow(2, pin);
if (value === 0) {
if ((this.oldGpioB & pinHexMask) === pinHexMask) {
this.oldGpioB = this.oldGpioB ^ pinHexMask;
this._send(TO_GPIOB, [this.oldGpioB]);
if ((this.gpioBState & pinHexMask) === pinHexMask) {
this.gpioBState = this.gpioBState ^ pinHexMask;
this._send(WRITE_GPIOB_ADDR, [this.gpioBState]);
}
}
if (value === 1) {
if ((this.oldGpioB & pinHexMask) !== pinHexMask) {
this.oldGpioB = this.oldGpioB ^ pinHexMask;
this._send(TO_GPIOB, [this.oldGpioB]);
if ((this.gpioBState & pinHexMask) !== pinHexMask) {
this.gpioBState = this.gpioBState ^ pinHexMask;
this._send(WRITE_GPIOB_ADDR, [this.gpioBState]);
}
}
};
Expand Down Expand Up @@ -168,7 +201,7 @@ var MCP23017 = (function() {
};

MCP23017.prototype.digitalRead = function (pin, callback) {
var register = pin >= 8 ? FROM_GPIOB : FROM_GPIOA; //get the register to read from
var register = pin >= 8 ? READ_GPIOB_ADDR : READ_GPIOA_ADDR; //get the register to read from
pin = pin >= 8 ? pin - 8 : pin; //remap the pin to internal value
var pinHexMask = Math.pow(2, pin); //create a hexMask

Expand All @@ -188,13 +221,13 @@ var MCP23017 = (function() {
};

MCP23017.prototype._initGpioA = function () {
this._send(DIRECTION_GPIOA, [this.oldADir]); //Set Direction to Output
this._send(TO_GPIOA, [0x0]); //clear all output states
this._send(REGISTER_GPIOA, [this.dirAState]); //Set Direction to Output
this._send(WRITE_GPIOA_ADDR, [0x0]); //clear all output states
};

MCP23017.prototype._initGpioB = function () {
this._send(DIRECTION_GPIOB, [this.oldBDir]); //Set Direction to Output
this._send(TO_GPIOB, [0x0]); //clear all output states
this._send(REGISTER_GPIOB, [this.dirBState]); //Set Direction to Output
this._send(WRITE_GPIOB_ADDR, [0x0]); //clear all output states
};

MCP23017.prototype._send = function (cmd, values) {
Expand Down
4 changes: 2 additions & 2 deletions package.json
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@@ -1,6 +1,6 @@
{
"name": "node-mcp23017",
"version": "0.0.2",
"version": "0.0.3",
"description": "Library to use the MCP23017 16bit I/O Expander with the Raspberry Pi",
"main": "main.js",
"author": "Kai Henzler",
Expand All @@ -10,6 +10,6 @@
},
"license": "MIT",
"dependencies": {
"i2c": "0.1.4"
"i2c": "0.2.3"
}
}

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