I2C.zip_PIC i2c

//------------------------------------------------------------------------------ // Keil Software, Inc. // // Project: EXAMPLE I2C PROGRAM for Philips 87LPC764 // // Filename: I2C_Master_Example.c // Version: 1.0.0 // Description: This file contains all the necessary routines to communicate // to I2C slave devices on the I2C bus. These routines use the // built in I2C hardware of the Philips MCUs. See application // note for futher discussion on I2C. // // This is example will communicate to a I2C devices. // Device 1 will be a serial ADC / DAC from Philips (PCF8591) // The example will gather the data and print it out the serial // port (9600, 8, N, 1). // // CPU Frequency: 11.0592 MHz // // Copyright 2000 - Keil Software, Inc. // All rights reserved. //------------------------------------------------------------------------------ //------------------------------------------------------------------------------ // Header files //------------------------------------------------------------------------------ #include "REG764.H" // Header file for LPC764 MCU #include <STDIO.H> // Standard I/O header file sbit P1_2 = 0x92; // Define the individual bit sbit P1_3 = 0x93; // Define the individual bit sbit P1_4 = 0x94; // Define the individual bit //------------------------------------------------------------------------------ // Macros //------------------------------------------------------------------------------ // Get high byte macro #define high_byte(x) ((x & 0xFF00) >> 8) //------------------------------------------------------------------------------ // Value Definitions //------------------------------------------------------------------------------ #define TRUE 0x01 // Value representing TRUE #define FALSE 0x00 // Value representing FALSE #define ON 0x01 // Value representing ON #define OFF 0x00 // Value representing OFF #define HIGH 0x01 // Value representing ON #define LOW 0x00 // Value representing OFF #define DELAY_WRITE 1000 // Value for delay write time #define DELAY_BLINK 25000 // Value for delay time - blink //------------------------------------------------------------------------------ // I/O Port Defines //------------------------------------------------------------------------------ #define LED P1_4 // LED Output //------------------------------------------------------------------------------ // I2C Peripheral Function Prototypes //------------------------------------------------------------------------------ // Writes a byte to the EEPROM void write_byte (unsigned char data_out, unsigned int address); // Reads a bytee from the EEPROM unsigned char read_byte (unsigned int address); //------------------------------------------------------------------------------ // I2C Function Prototypes //------------------------------------------------------------------------------ bit write_byte_I2C (unsigned char data_out);// Write single byte over I2C bit read_byte_I2C (unsigned char *data_in); // Read single byte from I2C // Send the I2C address and start signal bit send_slave_address_I2C (unsigned char slave_address); void stop_I2C (void); // Stops a I2C data transfer // Resends the I2C start signal bit restart_I2C (unsigned char slave_address); //------------------------------------------------------------------------------ // Support Function Prototypes //------------------------------------------------------------------------------ void initialize_system (void); // Initializes MCU, except I2C void delay_time (unsigned int time_end); // To pause execution for pre-determined time //------------------------------------------------------------------------------ // MAIN FUNCTION //------------------------------------------------------------------------------ void main (void) { unsigned int eeprom_address; initialize_system(); // Initialize RS-232 and rest of system printf("\n\rKeil Software, Inc.\n\r"); // Display starup message printf("LPC764 MCU I2C Example Test Program\n\r"); printf("Version 1.0.0\n\r"); printf("Copyright 2000 - Keil Software, Inc.\n\r"); printf("All rights reserved.\n\n\r"); P1M1 = 0x0C; // Set Port 1 Open Drain P1M2 = 0x0C; I2CFG = 0x22; // Config byte: 0 MAS CLRT1 T1, 00 CC (page 16) // In our case the config byte is: // Slave bit (7): 0 (we are not a slave) // Master bit (6): 0 (we are a master) // Clear T1 (5): 1 (Clear TI) // TI Run (4): 0 (set TI to run) // Not used (3): 0 // Not used (2): 0 // CT 1 (1): 1 (Set for highest CPU clock rate) // CT 0 (0): 0 printf("Writing data to EEPROM...."); for (eeprom_address = 0; eeprom_address < 75; eeprom_address++) write_byte((unsigned char)eeprom_address + 0x30, eeprom_address); printf("Done!\n\r"); printf("Reading from EEPROM...ASCII table!\n\r"); while (TRUE) // Infinite loop, never exits { for (eeprom_address = 0; eeprom_address < 75; eeprom_address++) { delay_time(DELAY_BLINK); // Blink LED with delay LED = ON; delay_time(DELAY_BLINK); LED = OFF; printf("Address: %3u Character: %c\n\r", eeprom_address, read_byte(eeprom_address)); } } } //------------------------------------------------------------------------------ // I2C Peripheral Function Prototypes //------------------------------------------------------------------------------ //------------------------------------------------------------------------------ // Procedure: write_byte // Inputs: data out, address // Outputs: none // Description: Writes a byte to the EEPROM given the address //------------------------------------------------------------------------------ void write_byte (unsigned char data_out, unsigned int address) { send_slave_address_I2C(0xA0); // Send I2C Start Transfer // Send identifier I2C address write_byte_I2C(high_byte(address)); // Send address to EEPROM write_byte_I2C((unsigned char)address); // Send address to EEPROM write_byte_I2C(data_out); // Send low byte to EEPROM stop_I2C(); // Send I2C Stop Transfer delay_time(DELAY_WRITE); // Delay a period of time to write } //------------------------------------------------------------------------------ // Procedure: read_byte // Inputs: address // Outputs: output byte // Description: Reads a byte from the EEPROM given the address //------------------------------------------------------------------------------ unsigned char read_byte (unsigned int address) { unsigned char data_in; send_slave_address_I2C(0xA0); // Send I2C Start Transfer // Send identifer I2C address write_byte_I2C(high_byte(address)); // Send address to EEPROM write_byte_I2C((unsigned char)address); // Send address to EEPROM restart_I2C(0xA1); // Send identifer I2C address read_byte_I2C(&data_in); // Read byte stop_I2C(); // Send I2C Stop Transfer return data_in; } //------------------------------------------------------------------------------ // I2C FUNCTIONS //------------------------------------------------------------------------------ //------------------------------------------------------------------------------ // Procedure: write_byte_I2C // Inputs: data output byte // Outputs: TRUE for Pass, FALSE for Failure // Description: Writes one byte over the I2C bus //------------------------------------------------------------------------------ bit write_byte_I2C (unsigned char data_out)