Guillaume Fricker / KS0108_PCF8574

KS0108 LCD LIB with I2C I/O expander PCF8574 for Databus

Dependencies:   BusEnums

Dependents:   Menu

PCF8574_DataBus.cpp@4:eeaa5069be9c, 2012-09-10 (annotated)

Committer:
GuiTwo
Date:
Mon Sep 10 16:33:35 2012 +0000
Revision:
4:eeaa5069be9c
Parent:
0:f2f71eab6aef 
Classe fille de MendedDisplay ( Classe abstraite)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
GuiTwo 0:f2f71eab6aef 1 /* PCF8574_DataBus - Use the PCF8574 I2C Port Extender for controlling the Data Bus
GuiTwo 0:f2f71eab6aef 2 * Copyright (c) 2011 Wim Huiskamp
GuiTwo 0:f2f71eab6aef 3 *
GuiTwo 0:f2f71eab6aef 4 * Released under the MIT License: http://mbed.org/license/mit
GuiTwo 0:f2f71eab6aef 5 *
GuiTwo 0:f2f71eab6aef 6 * version 0.2 Initial Release
GuiTwo 0:f2f71eab6aef 7 */
GuiTwo 0:f2f71eab6aef 8 #include "mbed.h"
GuiTwo 0:f2f71eab6aef 9 #include "PCF8574_DataBus.h"
GuiTwo 0:f2f71eab6aef 10
GuiTwo 0:f2f71eab6aef 11
GuiTwo 0:f2f71eab6aef 12 /** Create an PCF8574_DataBus object connected to the specified I2C object and using the specified deviceAddress
GuiTwo 0:f2f71eab6aef 13 *
GuiTwo 0:f2f71eab6aef 14 * @param I2C &i2c the I2C port to connect to
GuiTwo 0:f2f71eab6aef 15 * @param char deviceAddress the address of the PCF8574
GuiTwo 0:f2f71eab6aef 16 */
GuiTwo 0:f2f71eab6aef 17 PCF8574_DataBus::PCF8574_DataBus(I2C &i2c, char deviceAddress) : _i2c(i2c) {
GuiTwo 0:f2f71eab6aef 18 _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
GuiTwo 0:f2f71eab6aef 19 _readOpcode = deviceAddress | 0x01; // low order bit = 1 for read
GuiTwo 0:f2f71eab6aef 20 _init();
GuiTwo 0:f2f71eab6aef 21 }
GuiTwo 0:f2f71eab6aef 22
GuiTwo 0:f2f71eab6aef 23 /** Optimised DataBus write operation.
GuiTwo 0:f2f71eab6aef 24 * @param byte the datavalue to output on the bus
GuiTwo 0:f2f71eab6aef 25 */
GuiTwo 0:f2f71eab6aef 26 void PCF8574_DataBus::write(char byte) {
GuiTwo 0:f2f71eab6aef 27 char data[1];
GuiTwo 0:f2f71eab6aef 28
GuiTwo 0:f2f71eab6aef 29 data[0] = byte;
GuiTwo 0:f2f71eab6aef 30 if (_i2c.write(_writeOpcode, data, 1)!=0) // Write datavalue to bus
GuiTwo 0:f2f71eab6aef 31 {
GuiTwo 0:f2f71eab6aef 32 printf("erreur i2C write");
GuiTwo 0:f2f71eab6aef 33 }
GuiTwo 0:f2f71eab6aef 34 }
GuiTwo 0:f2f71eab6aef 35
GuiTwo 0:f2f71eab6aef 36 /** Optimised DataBus read operation.
GuiTwo 0:f2f71eab6aef 37 *
GuiTwo 0:f2f71eab6aef 38 * @returns current data from Databus
GuiTwo 0:f2f71eab6aef 39 */
GuiTwo 0:f2f71eab6aef 40 char PCF8574_DataBus::read() {
GuiTwo 0:f2f71eab6aef 41 char data[1];
GuiTwo 0:f2f71eab6aef 42
GuiTwo 0:f2f71eab6aef 43 //Make sure that databus is enabled for Read
GuiTwo 0:f2f71eab6aef 44 data[0] = 0xFF; // Init Port for datainput by Writing 0xFF
GuiTwo 0:f2f71eab6aef 45 _i2c.write(_writeOpcode, data, 1); // Write to bus
GuiTwo 0:f2f71eab6aef 46
GuiTwo 0:f2f71eab6aef 47 if( _i2c.read(_readOpcode, data, 1)!=0) // Read data from bus
GuiTwo 0:f2f71eab6aef 48 {
GuiTwo 0:f2f71eab6aef 49 printf("erreur i2C read");
GuiTwo 0:f2f71eab6aef 50 data[0]=0xAA;
GuiTwo 0:f2f71eab6aef 51 }
GuiTwo 0:f2f71eab6aef 52 return data[0];
GuiTwo 0:f2f71eab6aef 53 }
GuiTwo 0:f2f71eab6aef 54
GuiTwo 0:f2f71eab6aef 55
GuiTwo 0:f2f71eab6aef 56 /** Enable databus for Write or Read
GuiTwo 0:f2f71eab6aef 57 *
GuiTwo 0:f2f71eab6aef 58 * @param Bus_Dir bus_dir
GuiTwo 0:f2f71eab6aef 59 */
GuiTwo 0:f2f71eab6aef 60 void PCF8574_DataBus::busdir (Bus_Dir bus_dir) {
GuiTwo 0:f2f71eab6aef 61
GuiTwo 0:f2f71eab6aef 62 if (bus_dir == READ) {
GuiTwo 0:f2f71eab6aef 63 // Make sure that databus is enabled for READ
GuiTwo 0:f2f71eab6aef 64 //write(0xFF); // Init Port as input by Writing 0xFF
GuiTwo 0:f2f71eab6aef 65
GuiTwo 0:f2f71eab6aef 66 }
GuiTwo 0:f2f71eab6aef 67 else {
GuiTwo 0:f2f71eab6aef 68 // Make sure that databus is enabled for WRITE
GuiTwo 0:f2f71eab6aef 69 //write(0xFF); // Not really needed, just Init Port to safe settings
GuiTwo 0:f2f71eab6aef 70 }
GuiTwo 0:f2f71eab6aef 71 }
GuiTwo 0:f2f71eab6aef 72 void PCF8574_DataBus::output(void)
GuiTwo 0:f2f71eab6aef 73 {
GuiTwo 0:f2f71eab6aef 74 busdir (WRITE);
GuiTwo 0:f2f71eab6aef 75 }
GuiTwo 0:f2f71eab6aef 76 void PCF8574_DataBus::input(void)
GuiTwo 0:f2f71eab6aef 77 {
GuiTwo 0:f2f71eab6aef 78 busdir (READ);
GuiTwo 0:f2f71eab6aef 79 }
GuiTwo 0:f2f71eab6aef 80
GuiTwo 0:f2f71eab6aef 81
GuiTwo 0:f2f71eab6aef 82
GuiTwo 0:f2f71eab6aef 83 /** Init PCF8574_DataBus
GuiTwo 0:f2f71eab6aef 84 * @param
GuiTwo 0:f2f71eab6aef 85 * @returns
GuiTwo 0:f2f71eab6aef 86 */
GuiTwo 0:f2f71eab6aef 87 void PCF8574_DataBus::_init() {
GuiTwo 0:f2f71eab6aef 88
GuiTwo 0:f2f71eab6aef 89 busdir(WRITE); // Init Port as output
GuiTwo 0:f2f71eab6aef 90 }