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/*
* mcp23008.c:
* Extend wiringPi with the MCP 23008 I2C GPIO expander chip
* Copyright (c) 2013 Gordon Henderson
***********************************************************************
* This file is part of wiringPi:
* https://projects.drogon.net/raspberry-pi/wiringpi/
*
* wiringPi is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* wiringPi is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with wiringPi.
* If not, see <http://www.gnu.org/licenses/>.
***********************************************************************
*/
#include <stdio.h>
#include <pthread.h>
#include "wiringPi.h"
#include "wiringPiI2C.h"
#include "mcp23x0817.h"
#include "mcp23008.h"
/*
* myPinMode:
*********************************************************************************
*/
static void myPinMode (struct wiringPiNodeStruct *node, int pin, int mode)
{
int mask, old, reg ;
reg = MCP23x08_IODIR ;
mask = 1 << (pin - node->pinBase) ;
old = wiringPiI2CReadReg8 (node->fd, reg) ;
if (mode == OUTPUT)
old &= (~mask) ;
else
old |= mask ;
wiringPiI2CWriteReg8 (node->fd, reg, old) ;
}
/*
* myPullUpDnControl:
*********************************************************************************
*/
static void myPullUpDnControl (struct wiringPiNodeStruct *node, int pin, int mode)
{
int mask, old, reg ;
reg = MCP23x08_GPPU ;
mask = 1 << (pin - node->pinBase) ;
old = wiringPiI2CReadReg8 (node->fd, reg) ;
if (mode == PUD_UP)
old |= mask ;
else
old &= (~mask) ;
wiringPiI2CWriteReg8 (node->fd, reg, old) ;
}
/*
* myDigitalWrite:
*********************************************************************************
*/
static void myDigitalWrite (struct wiringPiNodeStruct *node, int pin, int value)
{
int bit, old ;
bit = 1 << ((pin - node->pinBase) & 7) ;
old = node->data2 ;
if (value == LOW)
old &= (~bit) ;
else
old |= bit ;
wiringPiI2CWriteReg8 (node->fd, MCP23x08_GPIO, old) ;
node->data2 = old ;
}
/*
* myDigitalRead:
*********************************************************************************
*/
static int myDigitalRead (struct wiringPiNodeStruct *node, int pin)
{
int mask, value ;
mask = 1 << ((pin - node->pinBase) & 7) ;
value = wiringPiI2CReadReg8 (node->fd, MCP23x08_GPIO) ;
if ((value & mask) == 0)
return LOW ;
else
return HIGH ;
}
/*
* mcp23008Setup:
* Create a new instance of an MCP23008 I2C GPIO interface. We know it
* has 8 pins, so all we need to know here is the I2C address and the
* user-defined pin base.
*********************************************************************************
*/
int mcp23008Setup (const int pinBase, const int i2cAddress)
{
int fd ;
struct wiringPiNodeStruct *node ;
if ((fd = wiringPiI2CSetup (i2cAddress)) < 0)
return FALSE ;
wiringPiI2CWriteReg8 (fd, MCP23x08_IOCON, IOCON_INIT) ;
node = wiringPiNewNode (pinBase, 8) ;
node->fd = fd ;
node->pinMode = myPinMode ;
node->pullUpDnControl = myPullUpDnControl ;
node->digitalRead = myDigitalRead ;
node->digitalWrite = myDigitalWrite ;
node->data2 = wiringPiI2CReadReg8 (fd, MCP23x08_OLAT) ;
return TRUE ;
}
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