//Initialize as a master
void TwoWire::begin(void)
{
if(i2cModule == NOT_ACTIVE) {
i2cModule = BOOST_PACK_WIRE;
}
ROM_SysCtlPeripheralEnable(g_uli2cPeriph[i2cModule]);
//Configure GPIO pins for I2C operation
ROM_GPIOPinConfigure(g_uli2cConfig[i2cModule][0]);
ROM_GPIOPinConfigure(g_uli2cConfig[i2cModule][1]);
ROM_GPIOPinTypeI2C(g_uli2cBase[i2cModule], g_uli2cSDAPins[i2cModule]);
ROM_GPIOPinTypeI2CSCL(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, speedMode);//Bus speed
if(speedMode==I2C_SPEED_FASTMODE_PLUS)//Force 1Mhz
{
uint32_t ui32TPR = ((F_CPU + (2 * 10 * 1000000l) - 1) / (2 * 10 * 1000000l)) - 1;
HWREG(MASTER_BASE + I2C_O_MTPR) = ui32TPR;
}
//force a stop condition
if(!ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]))
forceStop();
//Handle any startup issues by pulsing SCL
if(ROM_I2CMasterBusBusy(MASTER_BASE) || ROM_I2CMasterErr(MASTER_BASE)
|| !ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule])) {
uint8_t doI = 0;
ROM_GPIOPinTypeGPIOOutput(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
unsigned long mask = 0;
do {
for(unsigned long i = 0; i < 10 ; i++) {
if(speedMode==I2C_SPEED_FASTMODE_PLUS)
ROM_SysCtlDelay(F_CPU/1000000/3);//1000Hz=desired frequency, delay iteration=3 cycles
else if(speedMode==I2C_SPEED_FASTMODE)
ROM_SysCtlDelay(F_CPU/400000/3);//400Hz=desired frequency, delay iteration=3 cycles
else
ROM_SysCtlDelay(F_CPU/100000/3);//100Hz=desired frequency, delay iteration=3 cycles
mask = (i%2) ? g_uli2cSCLPins[i2cModule] : 0;
ROM_GPIOPinWrite(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule], mask);
}
doI++;
} while(ROM_I2CMasterBusBusy(MASTER_BASE) && doI < 100);
ROM_GPIOPinTypeI2CSCL(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
if(!ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]))
forceStop();
}
}
//Initialize as a master
void TwoWire::begin(void)
{
pinMode(RED_LED, OUTPUT);
if(i2cModule == NOT_ACTIVE) {
i2cModule = BOOST_PACK_WIRE;
}
ROM_SysCtlPeripheralEnable(g_uli2cPeriph[i2cModule]);
//Configure GPIO pins for I2C operation
ROM_GPIOPinConfigure(g_uli2cConfig[i2cModule][0]);
ROM_GPIOPinConfigure(g_uli2cConfig[i2cModule][1]);
ROM_GPIOPinTypeI2C(g_uli2cBase[i2cModule], g_uli2cSDAPins[i2cModule]);
ROM_GPIOPinTypeI2CSCL(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, false);//max bus speed=400kHz for gyroscope
//force a stop condition
if(!ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]))
forceStop();
//Handle any startup issues by pulsing SCL
if(ROM_I2CMasterBusBusy(MASTER_BASE) || ROM_I2CMasterErr(MASTER_BASE)
|| !ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule])){
uint8_t doI = 0;
ROM_GPIOPinTypeGPIOOutput(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
unsigned long mask = 0;
do{
for(unsigned long i = 0; i < 10 ; i++) {
ROM_SysCtlDelay(F_CPU/100000/3);//100Hz=desired frequency, delay iteration=3 cycles
mask = (i%2) ? g_uli2cSCLPins[i2cModule] : 0;
ROM_GPIOPinWrite(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule], mask);
}
doI++;
}while(ROM_I2CMasterBusBusy(MASTER_BASE) && doI < 100);
ROM_GPIOPinTypeI2CSCL(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
if(!ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]))
forceStop();
}
}
uint8_t TwoWire::endTransmission(uint8_t sendStop)
{
uint8_t error = I2C_MASTER_ERR_NONE;
if(TX_BUFFER_EMPTY) return 0;
//Wait for any previous transaction to complete
while(ROM_I2CMasterBusBusy(MASTER_BASE));
while(ROM_I2CMasterBusy(MASTER_BASE));
//Select which slave we are requesting data from
//false indicates we are writing to the slave
ROM_I2CMasterSlaveAddrSet(MASTER_BASE, txAddress, false);
while(ROM_I2CMasterBusy(MASTER_BASE));
unsigned long cmd = RUN_BIT | START_BIT;
error = sendTxData(cmd,txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
if(error) return error;
while(!TX_BUFFER_EMPTY) {
error = sendTxData(RUN_BIT,txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
if(error) return getError(error);
}
if(txWriteRomQuantity!=0) // Hey we have Rom Block data to transmit!
{
while(txWriteRomIndex != txWriteRomQuantity)
{
uint8_t c = *PtrTxRomBuffer++;
error = sendTxData(RUN_BIT,c);
txWriteRomIndex++;
if(error) return getError(error);
}
txWriteRomQuantity=0; // Clear to disable further tx
}
if(sendStop) {
while(ROM_I2CMasterBusy(MASTER_BASE));
HWREG(MASTER_BASE + I2C_O_MCS) = STOP_BIT;
while(ROM_I2CMasterBusy(MASTER_BASE));
currentState = IDLE;
}
else {
currentState = MASTER_TX;
}
// indicate that we are done transmitting
transmitting = 0;
return error;
}
uint8_t TwoWire::getRxData(unsigned long cmd) {
if (currentState == IDLE) while(ROM_I2CMasterBusBusy(MASTER_BASE));
HWREG(MASTER_BASE + I2C_O_MCS) = cmd;
while(ROM_I2CMasterBusy(MASTER_BASE));
uint8_t error = ROM_I2CMasterErr(MASTER_BASE);
if (error != I2C_MASTER_ERR_NONE) {
ROM_I2CMasterControl(MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP);
}
else {
while(ROM_I2CMasterBusy(MASTER_BASE));
rxBuffer[rxWriteIndex] = ROM_I2CMasterDataGet(MASTER_BASE);
rxWriteIndex = (rxWriteIndex + 1) % BUFFER_LENGTH;
}
return error;
}
uint8_t TwoWire::getRxData(unsigned long cmd) {
if (currentState == IDLE) while(ROM_I2CMasterBusBusy(MASTER_BASE));
HWREG(MASTER_BASE + I2C_O_MCS) = cmd;
while(ROM_I2CMasterBusy(MASTER_BASE));
uint8_t error = ROM_I2CMasterErr(MASTER_BASE);
if (error != I2C_MASTER_ERR_NONE) {
ROM_I2CMasterControl(MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP);
}
else {
if(speedMode==I2C_SPEED_STANDARD) //Fast modes works without delay (Tested on stellaris&GY-80)
delayMicroseconds(SLOWMODE_DELAYUS);
rxBuffer[rxWriteIndex] = ROM_I2CMasterDataGet(MASTER_BASE);
rxWriteIndex = (rxWriteIndex + 1) % BUFFER_LENGTH;
}
return error;
}
uint8_t TwoWire::endTransmission(uint8_t sendStop)
{
uint8_t error = I2C_MASTER_ERR_NONE;
digitalWrite(RED_LED, HIGH);
if(TX_BUFFER_EMPTY) return 0;
//Wait for any previous transaction to complete
while(ROM_I2CMasterBusBusy(MASTER_BASE)); // Here it hangs sometimes!
digitalWrite(RED_LED, LOW);
while(ROM_I2CMasterBusy(MASTER_BASE));
//Select which slave we are requesting data from
//false indicates we are writing to the slave
ROM_I2CMasterSlaveAddrSet(MASTER_BASE, txAddress, false);
while(ROM_I2CMasterBusy(MASTER_BASE));
unsigned long cmd = RUN_BIT | START_BIT;
error = sendTxData(cmd,txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
if(error) return error;
while(!TX_BUFFER_EMPTY) {
error = sendTxData(RUN_BIT,txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
if(error) return getError(error);
}
if(sendStop) {
while(ROM_I2CMasterBusy(MASTER_BASE));
HWREG(MASTER_BASE + I2C_O_MCS) = STOP_BIT;
while(ROM_I2CMasterBusy(MASTER_BASE));
currentState = IDLE;
}
else {
currentState = MASTER_TX;
}
// indicate that we are done transmitting
transmitting = 0;
return error;
}