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#define HIGH 1
#define LOW 0
#define TRUE 1
#define FALSE 0
//------------------------------------------------------------------------------
// I2C Functions - Master
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
// Routine: i2c_init
// Inputs: none
// Outputs: none
// Purpose: Initialize I2C for the ADu812C
//------------------------------------------------------------------------------
void i2c_init (void)
{
// To initialize we need the output
// data high, the clock high, and
// the I2C system in Master mode
I2CM = HIGH; // Set master mode
MDO = HIGH; // Set the data bit to HIGH
MDE = FALSE; // We are not using the pin yet
MCO = HIGH; // Set the clock bit to HIGH
}
//------------------------------------------------------------------------------
// Routine: i2c_start
// Inputs: none
// Outputs: none
// Purpose: Sends I2C Start Trasfer - State "B"
//------------------------------------------------------------------------------
void i2c_start (void)
{
// An I2C start sequence is defined as
// a High to Low Transistino on the data
// line as the CLK pin is high
MDE = TRUE; // Master Mode Data Output Enable: ON
MDO = HIGH;
MCO = HIGH;
MDO = LOW; // Master Mode Data Output: LOW
MDO = LOW; // Repeat for delay
MCO = LOW; // Master Mode Clock Output: LOW
}
//------------------------------------------------------------------------------
// Routine: i2c_stop
// Inputs: none
// Outputs: none
// Purpose: Sends I2C Stop Trasfer - State "C"
//------------------------------------------------------------------------------
void i2c_stop (void)
{
// An I2C start sequence is defined as
// a Low to High Transistino on the data
// line as the CLK pin is high
MDE = TRUE; // Master Mode Data Output Enable: ON
MDO = LOW; // Master Mode Data Output: LOW
MCO = HIGH; // Master Mode Clock Output: HIGH
MCO = HIGH; // Repeat for delay
MDO = HIGH; // Master Mode Data Output: LOW
}
//------------------------------------------------------------------------------
// Routine: i2c_write
// Inputs: output byte
// Outputs: none
// Purpose: Writes data over the I2C bus MSB -> LSB write
//------------------------------------------------------------------------------
bit i2c_write (unsigned char output_data)
{
unsigned char index;
// An I2C output byte is bits 7-0
// (MSB to LSB). Shift one bit at a time
// to the MDO output, and then clock the
// data to the I2C Slave
MDE = TRUE; // Master Mode Data Output Enable: ON
for(index = 0; index < 8; index++) // Send 8 bits out the port
{
// Output the data bit to the EEPROM
MDO = ((output_data & 0x80) ? 1 : 0);
output_data <<= 1; // Shift the byte by one bit
MCO = HIGH; // Clock the data into the EEPROM
MCO = HIGH; // Repeat for delay
MCO = LOW;
}
MDE = FALSE; // Put data pin into read mode
MCO = HIGH; // Get ACK bit
if (!MDI)
{
MCO = LOW; // Clock Low
return TRUE; // ACK from slave
}
else
{
MCO = LOW; // Clock Low
return FALSE; // No ACK
}
}
//------------------------------------------------------------------------------
// Routine: i2c_read
// Inputs: send_ack (if TRUE send the ACK signal)
// Outputs: input byte
// Purpose: Reads data from the I2C bus MSB -> LSB read
//------------------------------------------------------------------------------
unsigned char i2c_read (bit send_ack)
{
unsigned char index, input_data;
input_data = 0x00;
MDE = FALSE; // Put data pin into read mode
MCO = LOW; // Set clock LOW
for(index = 0; index < 8; index++) // Get 8 bits from the device
{
input_data <<= 1; // Shift the data right 1 bit
MCO = HIGH; // Clock the data into the register
MCO = HIGH; // Repeat for delay
MCO = LOW;
input_data |= MDI; // Read the data bit
}
MDE = TRUE; // Put data pin into write mode
if (send_ack) MDO = LOW; // Set data pin LOW to Ack the read
else MDO = HIGH; // Set data pin HIGH to Not Ack the read
MCO = HIGH; // Set the clock pin HIGH
MCO = HIGH; // Repeat for delay
MCO = LOW; // Set the clock pin LOW
MDO = LOW; // Set the data pin LOW
MDO = LOW; // Repeat for delay
MDE = LOW; // Put data pin into read mode
return input_data;
}
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