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/*********************************************************************
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*
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* Data EEPROM Access Routines
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*
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*********************************************************************
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* FileName: xeeprom.c
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* Dependencies: compiler.h
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* xeeprom.h
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* Processor: PIC18
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* Complier: MCC18 v1.00.50 or higher
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* HITECH PICC-18 V8.10PL1 or higher
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* Company: Microchip Technology, Inc.
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*
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* Software License Agreement
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*
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* The software supplied herewith by Microchip Technology Incorporated
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* (the “Company”) for its PICmicro® Microcontroller is intended and
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* supplied to you, the Company’s customer, for use solely and
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* exclusively on Microchip PICmicro Microcontroller products. The
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* software is owned by the Company and/or its supplier, and is
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* protected under applicable copyright laws. All rights are reserved.
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* Any use in violation of the foregoing restrictions may subject the
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* user to criminal sanctions under applicable laws, as well as to
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* civil liability for the breach of the terms and conditions of this
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* license.
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*
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* THIS SOFTWARE IS PROVIDED IN AN “AS IS” CONDITION. NO WARRANTIES,
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* WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED
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* TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT,
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* IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR
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* CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
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*
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* This is a modified version of C18 library functions.
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* This version supports data EEPROM with two bytes of address.
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* It still uses some of the routines from C18 library.
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*
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*
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* HiTech PICC18 Compiler Options excluding device selection:
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* -FAKELOCAL -G -O -Zg -E -C
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*
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*
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* Author Date Comment
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*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* Nilesh Rajbharti 5/20/02 Original (Rev. 1.0)
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********************************************************************/
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#include "compiler.h"
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#include "xeeprom.h"
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#define IdleI2C() while ( ( SSPCON2 & 0x1F ) | ( SSPSTAT_R_W ) );
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#define StartI2C() SSPCON2_SEN=1
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#define RestartI2C() SSPCON2_RSEN=1
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#define StopI2C() SSPCON2_PEN=1
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#define NotAckI2C() SSPCON2_ACKDT=1, SSPCON2_ACKEN=1
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static unsigned char getcI2C( void );
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static unsigned char WriteI2C( unsigned char data_out );
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XEE_RESULT XEEClose(void);
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/*********************************************************************
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* Function: void XEEInit(unsigned char baud)
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*
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* PreCondition: None
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*
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* Input: baud - SSPADD value for bit rate.
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*
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* Output: None
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*
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* Side Effects: None
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*
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* Overview: Initialize I2C module to communicate to serial
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* EEPROM.
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*
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* Note: None
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********************************************************************/
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#define MASTER 8 /* I2C Master mode */
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/* SSPSTAT REGISTER */
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#define SLEW_OFF 0xC0 /* Slew rate disabled for 100kHz mode */
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#define SLEW_ON 0x00 /* Slew rate enabled for 400kHz mode */
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#define SSPENB 0x20 /* Enable serial port and configures
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SCK, SDO, SDI */
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void XEEInit(unsigned char baud)
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{
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SSPSTAT &= 0x3F; // power on state
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SSPCON1 = 0x00; // power on state
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SSPCON2 = 0x00; // power on state
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SSPCON1 |= MASTER; // select serial mode
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SSPSTAT |= SLEW_ON; // slew rate on/off
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TRISC_RC3 = 1; // Set SCL (PORTC,3) pin to input
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TRISC_RC4 = 1; // Set SDA (PORTC,4) pin to input
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SSPCON1 |= SSPENB; // enable synchronous serial port
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SSPADD = baud;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEESetAddr(unsigned char control,
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* XEE_ADDR address)
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*
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* PreCondition: XEEInit() is already called.
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*
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* Input: control - data EEPROM control code
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* address - address to be set
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Modifies internal address counter of EEPROM.
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*
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* Note: This function does not release the I2C bus.
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* User must close XEEClose() after this function
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* is called.
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********************************************************************/
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XEE_RESULT XEESetAddr(unsigned char control, XEE_ADDR address)
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{
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union
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{
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unsigned short int Val;
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struct
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{
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unsigned char LSB;
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unsigned char MSB;
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} bytes;
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} tempAddress;
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tempAddress.Val = address;
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IdleI2C(); // ensure module is idle
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StartI2C(); // initiate START condition
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while ( SSPCON2_SEN ); // wait until start condition is over
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if ( PIR2_BCLIF ) // test for bus collision
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return XEE_BUS_COLLISION; // return with Bus Collision error
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if ( WriteI2C( control ) ) // write 1 byte
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return XEE_BUS_COLLISION; // set error for write collision
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IdleI2C(); // ensure module is idle
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if ( !SSPCON2_ACKSTAT ) // test for ACK condition, if received
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{
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if ( WriteI2C( tempAddress.bytes.MSB ) ) // WRITE word address to EEPROM
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return XEE_BUS_COLLISION; // return with write collision error
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IdleI2C(); // ensure module is idle
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if ( WriteI2C( tempAddress.bytes.LSB ) ) // WRITE word address to EEPROM
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return XEE_BUS_COLLISION; // return with write collision error
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IdleI2C(); // ensure module is idle
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if ( !SSPCON2_ACKSTAT ) // test for ACK condition received
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return XEE_SUCCESS;
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else
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return XEE_NAK; // return with Not Ack error
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}
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else
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return XEE_NAK; // return with Not Ack error
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}
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/*********************************************************************
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* Function: XEE_RESULT XEEBeginRead(unsigned char control,
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* XEE_ADDR address)
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*
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* PreCondition: XEEInit() is already called.
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*
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* Input: control - EEPROM control and address code.
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* address - Address at which read is to be performed.
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Sets internal address counter to given address.
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* Puts EEPROM in sequential read mode.
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*
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* Note: This function does not release I2C bus.
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* User must call XEEEndRead() when read is not longer
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* needed; I2C bus will released after XEEEndRead()
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* is called.
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********************************************************************/
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XEE_RESULT XEEBeginRead(unsigned char control, XEE_ADDR address )
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{
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unsigned char r;
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r = XEESetAddr(control, address);
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if ( r != XEE_SUCCESS )
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return r;
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r = XEEClose();
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if ( r != XEE_SUCCESS )
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return r;
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IdleI2C();
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StartI2C();
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while( SSPCON2_SEN );
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if ( PIR2_BCLIF )
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return XEE_BUS_COLLISION;
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if ( WriteI2C(control+1) )
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return XEE_BUS_COLLISION;
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IdleI2C();
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if ( !SSPCON2_ACKSTAT )
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return XEE_SUCCESS;
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return XEE_NAK;
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}
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XEE_RESULT XEEWrite(unsigned char val)
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{
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IdleI2C(); // ensure module is idle
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if ( WriteI2C( val ) ) // data byte for EEPROM
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return XEE_BUS_COLLISION; // set error for write collision
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IdleI2C();
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if ( !SSPCON2_ACKSTAT )
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return XEE_SUCCESS;
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return XEE_NAK;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEEEndWrite(void)
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*
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* PreCondition: XEEInit() && XEEBeginWrite() are already called.
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*
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* Input: None
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Instructs EEPROM to begin write cycle.
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*
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* Note: Call this function after either page full of bytes
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* written or no more bytes are left to load.
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* This function initiates the write cycle.
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* User must call for XEEWait() to ensure that write
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* cycle is finished before calling any other
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* routine.
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********************************************************************/
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XEE_RESULT XEEEndWrite(void)
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{
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IdleI2C();
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StopI2C();
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while(SSPCON2_PEN);
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return XEE_SUCCESS;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEERead(void)
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*
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* PreCondition: XEEInit() && XEEBeginRead() are already called.
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*
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* Input: None
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Reads next byte from EEPROM; internal address
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* is incremented by one.
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*
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* Note: This function does not release I2C bus.
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* User must call XEEEndRead() when read is not longer
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* needed; I2C bus will released after XEEEndRead()
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* is called.
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********************************************************************/
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unsigned char XEERead(void)
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{
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getcI2C();
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while( SSPCON2_RCEN ); // check that receive sequence is over.
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SSPCON2_ACKDT = 0; // Set ack bit
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SSPCON2_ACKEN = 1;
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while( SSPCON2_ACKEN );
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return SSPBUF;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEEEndRead(void)
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*
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* PreCondition: XEEInit() && XEEBeginRead() are already called.
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*
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* Input: None
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Ends sequential read cycle.
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*
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* Note: This function ends seuential cycle that was in
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* progress. It releases I2C bus.
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********************************************************************/
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XEE_RESULT XEEEndRead(void)
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{
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getcI2C();
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while( SSPCON2_RCEN ); // check that receive sequence is over.
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NotAckI2C();
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while( SSPCON2_ACKEN );
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StopI2C();
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while( SSPCON2_PEN );
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return XEE_SUCCESS;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEEReadArray(unsigned char control,
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* XEE_ADDR address,
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* unsigned char *buffer,
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* unsigned char length)
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*
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* PreCondition: XEEInit() is already called.
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*
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* Input: control - EEPROM control and address code.
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* address - Address from where array is to be read
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* buffer - Caller supplied buffer to hold the data
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* length - Number of bytes to read.
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*
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* Output: XEE_SUCCESS if successful
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Reads desired number of bytes in sequential mode.
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* This function performs all necessary steps
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* and releases the bus when finished.
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*
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* Note: None
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********************************************************************/
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XEE_RESULT XEEReadArray(unsigned char control,
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XEE_ADDR address,
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unsigned char *buffer,
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unsigned char length)
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{
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XEE_RESULT r;
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r = XEEBeginRead(control, address);
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if ( r != XEE_SUCCESS )
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return r;
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while( length-- )
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*buffer++ = XEERead();
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r = XEEEndRead();
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return r;
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}
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XEE_RESULT XEEClose(void)
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{
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IdleI2C();
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StopI2C();
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while( SSPCON2_PEN ); // wait until stop condition is over.
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if ( PIR2_BCLIF )
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return XEE_BUS_COLLISION;
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return XEE_SUCCESS;
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}
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/*********************************************************************
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* Function: XEE_RESULT XEEIsBusy(unsigned char control)
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*
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* PreCondition: XEEInit() is already called.
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*
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* Input: control - EEPROM control and address code.
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*
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* Output: XEE_READY if EEPROM is not busy
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* XEE_BUSY if EEPROM is busy
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* other value if failed.
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*
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* Side Effects: None
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*
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* Overview: Requests ack from EEPROM.
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*
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* Note: None
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********************************************************************/
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XEE_RESULT XEEIsBusy(unsigned char control)
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{
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XEE_RESULT r;
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IdleI2C(); // ensure module is idle
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StartI2C(); // initiate START condition
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while ( SSPCON2_SEN ); // wait until start condition is over
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if ( PIR2_BCLIF ) // test for bus collision
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{
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return XEE_BUS_COLLISION; // return with Bus Collision error
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}
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else
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{
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if ( WriteI2C( control ) ) // write byte - R/W bit should be 0
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return XEE_BUS_COLLISION; // set error for write collision
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IdleI2C(); // ensure module is idle
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if ( PIR2_BCLIF ) // test for bus collision
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return XEE_BUS_COLLISION; // return with Bus Collision error
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if ( !SSPCON2_ACKSTAT )
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r = XEE_READY;
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else
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r = XEE_BUSY;
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#if 0
|
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while ( SSPCON2_ACKSTAT ) // test for ACK condition received
|
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{
|
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RestartI2C(); // initiate Restart condition
|
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while ( SSPCON2_RSEN ); // wait until re-start condition is over
|
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if ( PIR2_BCLIF ) // test for bus collision
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return XEE_BUS_COLLISION; // return with Bus Collision error
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if ( WriteI2C( control ) ) // write byte - R/W bit should be 0
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return XEE_BUS_COLLISION; // set error for write collision
|
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IdleI2C(); // ensure module is idle
|
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}
|
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#endif
|
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}
|
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StopI2C(); // send STOP condition
|
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while ( SSPCON2_PEN ); // wait until stop condition is over
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if ( PIR2_BCLIF ) // test for bus collision
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return XEE_BUS_COLLISION; // return with Bus Collision error
|
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return r;
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//return XEE_READY; // return with no error
|
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}
|
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|
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|
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/********************************************************************
|
453 |
* Function Name: WriteI2C *
|
454 |
* Return Value: Status byte for WCOL detection. *
|
455 |
* Parameters: Single data byte for I2C bus. *
|
456 |
* Description: This routine writes a single byte to the *
|
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* I2C bus. *
|
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********************************************************************/
|
459 |
static unsigned char WriteI2C( unsigned char data_out )
|
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{
|
461 |
SSPBUF = data_out; // write single byte to SSPBUF
|
462 |
if ( SSPCON1_WCOL ) // test if write collision occurred
|
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return ( -1 ); // if WCOL bit is set return negative #
|
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else
|
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{
|
466 |
while( SSPSTAT_BF ); // wait until write cycle is complete
|
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return ( 0 ); // if WCOL bit is not set return non-negative #
|
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}
|
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}
|
470 |
|
471 |
|
472 |
|
473 |
/********************************************************************
|
474 |
* Function Name: ReadI2C *
|
475 |
* Return Value: contents of SSPBUF register *
|
476 |
* Parameters: void *
|
477 |
* Description: Read single byte from I2C bus. *
|
478 |
********************************************************************/
|
479 |
static unsigned char getcI2C( void )
|
480 |
{
|
481 |
SSPCON2_RCEN = 1; // enable master for 1 byte reception
|
482 |
while ( !SSPSTAT_BF ); // wait until byte received
|
483 |
return ( SSPBUF ); // return with read byte
|
484 |
}
|