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Espruino module for I2C device PCF8574
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| /* | |
| Created a module for the GPIO extender PCF8574X. | |
| Like to share it to get some feed back and fixes before it is added to EspruinoDocs as a new device. | |
| ``` | |
| const SCL = < SCL pin >; | |
| const SDA = < SDA pin>; | |
| const INT = < interrupt pin >; | |
| const IN = 0; // to define device as input | |
| const OUT = 1; // to define device as output | |
| I2C1.setup({sda:SDA,scl:SCL}); | |
| // use extender as input device with interrupt | |
| var extenderIn = require("PCF8574X")(I2C1,56, IN, true); | |
| // read value of all pins | |
| console.log("values for all pins:", extenderIn.read()); | |
| // read value of a single pin | |
| console.log("value for pin 0:", extenderIn.readPin(0); | |
| // enable interrupt | |
| // extenderIn.enableINT(<callback> ,<interrupt pin>); | |
| extenderIn.enableINT(function(){console.log("value changed");},INT); | |
| // use extender as input device | |
| var extenderOut = require("PCF8574X")(I2C1,32, OUT, true); | |
| extenterOut.write(255); | |
| ``` | |
| */ | |
| class PCF8574X { | |
| constructor(i2c, i2ca, mode) { | |
| this.i2c = i2c; | |
| this.i2ca = i2ca; | |
| this.mode = ( typeof(mode) === "undefined" ? 1 : mode); | |
| // stuff for watching interrupt | |
| this.watchPin = null; | |
| this.callback = null; | |
| this.id = 0; | |
| } | |
| write(val){ | |
| if ( this.mode ) | |
| this.i2c.writeTo( this.i2ca, val ^ 255 ); | |
| } | |
| writePin(pin, val) { | |
| val = !val + 0; | |
| if ( this.mode ) { | |
| var value = this.i2c.readFrom(this.i2ca,1)[0]; | |
| if ( val ) | |
| this.i2c.writeTo(this.i2ca, value | 1 << pin ); | |
| else | |
| this.i2c.writeTo(this.i2ca, value & ~(1 << pin)); | |
| } | |
| } | |
| read(){ | |
| var val; | |
| if ( !this.mode ) { | |
| val = this.i2c.readFrom(this.i2ca,1)[0]; | |
| return val^255; | |
| } | |
| } | |
| readPin(pin) { | |
| var val; | |
| if ( !this.mode ) { | |
| val = ((this.i2c.readFrom(this.i2ca,1)[0]>>pin) % 2 ); | |
| return ! val + 0; | |
| } | |
| } | |
| enableINT(callback, pin) { | |
| if ( !this.mode ) { | |
| this.watchPin = pin; | |
| this.callback = callback; | |
| this.id = setWatch( this.callback, | |
| this.watchPin, | |
| { repeat : true, edge : 'falling', debounce : 10 } | |
| ); | |
| } | |
| } | |
| disableINT() { | |
| if ( !this.mode ) { | |
| if ( this.id ) { | |
| clearWatch( this.id ); | |
| this.watchPin = null; | |
| this.callback = null; | |
| this.id = 0; | |
| } | |
| } | |
| } | |
| } | |
| exports = PCF8574X; |
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