//------------------------------------------------------------------------------
// 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)
