void i2cSlaveInitialize(I2cBusConnection* i2cBusConnection) {
// Avoid more than one initialization
if (i2cBusConnection->opened) {
writeError(I2C_SLAVE_ALREADY_INITIALIZED);
return;
}
i2cBusConnection->opened = true;
appendString(getDebugOutputStreamLogger(), "I2C Slave Write Address=");
appendHex2(getDebugOutputStreamLogger(), i2cBusConnection->i2cAddress);
appendCRLF(getDebugOutputStreamLogger());
if (i2cBusConnection == NULL) {
// Enable the I2C module with clock stretching enabled
OpenI2C1(I2C_ON | I2C_7BIT_ADD | I2C_STR_EN, BRG_VAL);
// 7-bit I2C slave address must be initialised here.
// we shift because i2c address is shift to the right
// to manage read and write address
I2C1ADD = i2cBusConnection->i2cAddress >> 1;
I2C1MSK = 0;
// Interruption on I2C Slave
// -> Priority of I2C Slave interruption
mI2C1SetIntPriority(I2C_INT_PRI_3 | I2C_INT_SLAVE);
// -> Enable Interruption Flag => See the same code in interruption
mI2C1SClearIntFlag();
// Enable I2C (MACRO)
EnableIntSI2C1;
}
/**
* Function Name: SI2C1Interrupt
* Description : This is the ISR for I2C1 Slave interrupt.
*/
void __ISR(_I2C_1_VECTOR, ipl3) _SlaveI2CHandler(void)
{
// TODO : Find the right i2cBusConnection
I2cBusConnection* i2cBusConnection = NULL;
// last byte received is address and not data
char isData = I2C1STATbits.D_A;
char read = I2C1STATbits.R_W;
char isStart = I2C1STATbits.S;
char isSclRelease = I2C1CONbits.SCLREL;
char readBufferFull = I2C1STATbits.RBF;
// check for MASTER and Bus events and respond accordingly
if (IFS0bits.I2C1MIF == 1) {
mI2C1MClearIntFlag();
return;
}
if (IFS0bits.I2C1BIF == 1) {
mI2C1BClearIntFlag();
return;
}
StreamLink* i2cStreamLink = getI2cStreamLink();
// handle the incoming message
// Master want to write and send the address
if (isStart && !read && !isData && readBufferFull) {
// R/W bit = 0 --> indicates data transfer is input to slave
// D/A bit = 0 --> indicates last byte was address
// reset any state variables needed by a message sequence
// perform a dummy read of the address
portableSlaveReadI2C(i2cBusConnection);
// release the clock to restart I2C
portableSlaveClockRelease(i2cBusConnection);
}
// Master WRITE (InputStream)
else if (isStart && !read && isData && readBufferFull) {
// R/W bit = 0 --> indicates data transfer is input to slave
// D/A bit = 1 --> indicates last byte was data
int data = portableSlaveReadI2C(i2cBusConnection);
Buffer* i2cSlaveInputBuffer = i2cStreamLink->inputBuffer;
OutputStream* outputStream = getOutputStream(i2cSlaveInputBuffer);
// Read data from the Master
append(outputStream, data);
// for debug support
appendI2cDebugInputChar(data);
// release the clock to restart I2C
portableSlaveClockRelease(i2cBusConnection);
}
// Master send the address and want to read
else if (isStart && read && !isData) {
// R/W bit = 1 --> indicates data transfer is output from slave
// D/A bit = 0 --> indicates last byte was address
portableSlaveReadI2C(i2cBusConnection);
Buffer* i2cSlaveOutputBuffer = i2cStreamLink->outputBuffer;
// Get an inputStream to read the buffer to send to the master
InputStream* i2cInputStream = getInputStream(i2cSlaveOutputBuffer);
// There is available data
if (i2cInputStream->availableData(i2cInputStream)) {
char c = i2cInputStream->readChar(i2cInputStream);
// for debug support
appendI2cDebugOutputChar(c);
portableSlaveWriteI2C(i2cBusConnection, c);
} else {
portableSlaveWriteI2C(i2cBusConnection, I2C_SLAVE_NO_DATA_IN_READ_BUFFER);
}
}
// Master want to read
else if (isStart && read && isData && !isSclRelease) {
// R/W bit = 1 --> indicates data transfer is output from slave
// D/A bit = 1 --> indicates last byte was data
Buffer* i2cSlaveOutputBuffer = i2cStreamLink->outputBuffer;
// Get an inputStream to read the buffer to send to the master
InputStream* i2cInputStream = getInputStream(i2cSlaveOutputBuffer);
// There is available data
if (i2cInputStream->availableData(i2cInputStream)) {
char c = i2cInputStream->readChar(i2cInputStream);
// for debug support
appendI2cDebugInputChar(c);
// we send it to the master
portableSlaveWriteI2C(i2cBusConnection, c);
} else {
// There is no data, we send it to the master
portableSlaveWriteI2C(i2cBusConnection, I2C_SLAVE_NO_DATA_IN_READ_BUFFER);
}
}
// finally clear the slave interrupt flag
mI2C1SClearIntFlag();
}
