//*****************************************************************************
//
//! \brief Write one byte to special register
//!
//! \param RegAddr specifies the target register address.
//! \param Data is the data written to target register.
//!
//! This function is to write one byte to PCF8574 register,one byte will be
//! writen in appointed address.
//!
//! \note internal function, used in this file only.
//!
//! \return Indicate the status of operation which can be one of the following
//! value \b SUCCESS or \b FAILURE .
//
//*****************************************************************************
static Result _I2CRegWriteByte(uint8_t RegAddr, uint8_t Data)
{
Result retv = SUCCESS;
// Begin to I2C Transfer
// first send START signal to control I2C bus
// then send 7-bit address and R/W bit to I2C salve
// at last send target register address
retv = xI2CMasterWriteS1(PCF8574_PIN_I2C_PORT, PCF8574_I2C_ADDR,
RegAddr, I2C_TRAN_NOT_END);
if(retv != SUCCESS)
{
return (FAILURE);
}
// Send the wanted data to I2C bus
// then Send STOP signal to release I2C bus
retv = xI2CMasterWriteS2(PCF8574_PIN_I2C_PORT, Data, I2C_TRAN_END);
if(retv != SUCCESS)
{
return (FAILURE);
}
return(SUCCESS);
}
//*****************************************************************************
//
//! \brief Write 4-bit data or command to the SPLC780D through PCA8574.
//!
//! \param ucRS determines if the IR or DR to select.
//!
//! \return None.
//
//*****************************************************************************
void
SPLC780Write4Bit(unsigned char ucDat)
{
ucDat = ucDat | ucBacklightState | SPLC780_RW_WRITE;
//
//! input the 4-bit data
//
xI2CMasterWriteS1(ulMaster, SPLC780_I2C_Addr, ucDat, xfalse);
//
//! latch the 4-bit data
//
xI2CMasterWriteS2(ulMaster, (ucDat | SPLC780_E_ENABLE), xfalse);
xSysCtlDelay(200);
xI2CMasterWriteS2(ulMaster, (ucDat | SPLC780_E_DISABLE), xtrue);
}
//*****************************************************************************
//
//! \brief Read the state or data from the SPLC780D.
//!
//! \param ucRS determines if the IR or DR to select.
//!
//! The parameter of ucRS can be:
//! - \ref SPLC780_RS_COMMAND - select the IR.
//! - \ref SPLC780_RS_DATA - select the DR.
//!
//! \return None.
//
//*****************************************************************************
unsigned char
SPLC780Read(unsigned char ucRS)
{
unsigned char ucTemp, ucData = 0;
//
// Check Arguments.
//
xASSERT((ucRS == SPLC780_RS_COMMAND) || (ucRS == SPLC780_RS_DATA));
//
// RS:Command, RW:Write, E:Enable
//
ucTemp = (ucRS | SPLC780_RW_READ | SPLC780_E_DISABLE | ucBacklightState);
xI2CMasterWriteS1(ulMaster, SPLC780_I2C_Addr, ucTemp, xfalse);
xSysCtlDelay(20);
ucTemp = (ucRS | SPLC780_RW_READ | SPLC780_E_ENABLE | ucBacklightState);
xI2CMasterWriteS2(ulMaster, ucTemp, xfalse);
//
// Read the Data
//
xI2CMasterReadS2(ulMaster, &ucData, xfalse);
ucTemp = (ucRS | SPLC780_RW_READ | SPLC780_E_DISABLE | ucBacklightState);
xI2CMasterWriteS2(ulMaster, ucTemp, xfalse);
xSysCtlDelay(20);
ucTemp = (ucRS | SPLC780_RW_READ | SPLC780_E_ENABLE | ucBacklightState);
xI2CMasterWriteS2(ulMaster, ucTemp, xfalse);
//
// Read the Data
//
xI2CMasterReadS2(ulMaster, &ucTemp, xtrue);
ucData = ((ucData << 4) & 0xf0) | (ucTemp & 0x0f);
return ucData;
}
//Writes data to the I2C.
size_t WireClass::write(uint8_t data){
if(transmitting){
// in master transmitter mode
// don't bother if buffer is full
if(txBufferLength >= BUFFER_LENGTH){
setWriteError();
return 0;
}
// put byte in tx buffer
txBuffer[txBufferIndex] = data;
++txBufferIndex;
// update amount in buffer
txBufferLength = txBufferIndex;
} else {
// in slave send mode
// reply to master
ulW++;
if(ulW == 1)
xI2CMasterWriteS1(i2cPort, (unsigned char)txAddress, data, xfalse);
else
xI2CMasterWriteS2(i2cPort, (unsigned char)data, xfalse);
}
return 1;
}