static int i2c_do_read(i2c_t *obj, char * data, int last) {
uint32_t i2c_addrs[] = I2C_BASE_ADDRS;
if (last) {
I2C_HAL_SendNak(i2c_addrs[obj->instance]);
} else {
I2C_HAL_SendAck(i2c_addrs[obj->instance]);
}
*data = (I2C_HAL_ReadByte(i2c_addrs[obj->instance]) & 0xFF);
// start rx transfer and wait the end of the transfer
return i2c_wait_end_rx_transfer(obj);
}
void TwoWire::onService(void)
{
//interrupt handler
uint8_t i2cData = 0x00;
bool wasArbLost = I2C_HAL_GetStatusFlag(instance, kI2CArbitrationLost);
bool addressed = I2C_HAL_GetStatusFlag(instance, kI2CAddressAsSlave);
bool stopIntEnabled = false;
bool startDetected = I2C_HAL_GetStartFlag(instance);
bool startIntEnabled = I2C_HAL_GetStartStopIntCmd(instance);
bool stopDetected = I2C_HAL_GetStopFlag(instance);
stopIntEnabled = startIntEnabled;
/* Get current slave transfer direction */
i2c_direction_t direction = I2C_HAL_GetDirMode(instance);
/*--------------- Handle START, STOP or REPEAT START ------------------*/
if (stopIntEnabled && (startDetected || stopDetected))
{
if(startDetected)
I2C_HAL_ClearStartFlag(instance);
if(stopDetected)
I2C_HAL_ClearStopFlag(instance);
I2C_HAL_ClearInt(instance);
if(slaveBufferLength)
{
if(onReceiveCallback)
{
receiving_slave = true;
onReceiveCallback(slaveBufferLength);
receiving_slave = false;
}
slaveBufferIndex = 0;
slaveBufferLength = 0;
}
return;
}
/* Clear I2C IRQ.*/
I2C_HAL_ClearInt(instance);
if (wasArbLost)
{
I2C_HAL_ClearArbitrationLost(instance);
if (!addressed)
{
master_state = MASTER_STATE_ARB_LOST;
return;
}
}
if(I2C_HAL_IsMaster(instance))
{
if (direction == kI2CSend)
{
//check for NAK
/* Check whether we got an ACK or NAK from the former byte we sent */
if (I2C_HAL_GetStatusFlag(instance, kI2CReceivedNak))
{
master_state = MASTER_STATE_TX_NAK;
}
else if(transmitting_master)
{
/* Continue send if still have data. TxSize/txBuff index need
* increment first because one byte is already sent in order
* to trigger interrupt */
if (txBufferIndex < txBufferLength)
{
/* Transmit next byte and update buffer index */
I2C_HAL_WriteByte(instance, txBuffer[txBufferIndex++]);
}
else
{
/* Finish send data, send STOP, disable interrupt */
master_state = MASTER_STATE_COMPLETE;
}
}
else
{
master_state = MASTER_STATE_READ_READY; //address sent for a read
}
}
else
{
switch (--rxBufferQuantity)
{
case 0x0U:
/* Finish receive data, send STOP, disable interrupt */
master_state = MASTER_STATE_COMPLETE;
if(master_send_stop)
I2C_HAL_SendStop(instance);
else
I2C_HAL_SendStart(instance);
break;
case 0x1U:
/* For the byte before last, we need to set NAK */
I2C_HAL_SendNak(instance);
break;
default :
I2C_HAL_SendAck(instance);
break;
}
rxBuffer[rxBufferLength++] = I2C_HAL_ReadByte(instance);
}
return;
}
/*--------------- Handle Address ------------------*/
/* Addressed only happens when receiving address. */
if (addressed) /* Slave is addressed. */
{
/* Master read from Slave. Slave transmit.*/
if (I2C_HAL_GetStatusFlag(instance, kI2CSlaveTransmit))
{
/* Switch to TX mode*/
I2C_HAL_SetDirMode(instance, kI2CSend);
transmitting_slave = true;
slaveBufferIndex = 0;
slaveBufferLength = 0;
if (onRequestCallback)
onRequestCallback(); //this needs to load the transmit buffer
else
// create a default 1-byte response
write((uint8_t) 0);
}
else /* Master write to Slave. Slave receive.*/
{
/* Switch to RX mode.*/
I2C_HAL_SetDirMode(instance, kI2CReceive);
I2C_HAL_SendAck(instance);
/* Read dummy character.*/
I2C_HAL_ReadByte(instance);
slaveBufferIndex = 0;
slaveBufferLength = 0;
}
}
/*--------------- Handle Transfer ------------------*/
else
{
/* Handle transmit */
if (direction == kI2CSend)
{
if (I2C_HAL_GetStatusFlag(instance, kI2CReceivedNak))
{
/* Switch to RX mode.*/
I2C_HAL_SetDirMode(instance, kI2CReceive);
/* Read dummy character to release bus */
I2C_HAL_ReadByte(instance);
transmitting_slave = false;
slaveBufferIndex = 0;
slaveBufferLength = 0;
}
else /* ACK from receiver.*/
{
transmitting_slave = true;
}
}
/* Handle receive */
else
{
/* Get byte from data register */
I2C_HAL_SendAck(instance);
i2cData = I2C_HAL_ReadByte(instance);
if(slaveBufferLength < BUFFER_LENGTH)
slaveBuffer[slaveBufferLength++] = i2cData;
}
}
if (transmitting_slave)
{
/* Send byte to data register */
if (slaveBufferIndex < slaveBufferLength)
{
I2C_HAL_WriteByte(instance, slaveBuffer[slaveBufferIndex++]);
if (slaveBufferIndex >= slaveBufferLength)
{
slaveBufferIndex = 0;
slaveBufferLength = 0;
transmitting_slave = false;
}
}
else
transmitting_slave = false;
}
}
uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint8_t sendStop)
{
if(quantity == 0) return 0;
uint32_t t0 = millis();
while(I2C_HAL_GetStatusFlag(instance, kI2CBusBusy) && !I2C_HAL_IsMaster(instance))
{
if(millis() - t0 >= 25)
return 4; //timeout
}
if(quantity > BUFFER_LENGTH){
quantity = BUFFER_LENGTH;
}
rxBufferQuantity = quantity;
rxBufferIndex = 0;
rxBufferLength = 0;
uint16_t slaveAddr = (address << 1U) | 1;
if(!sendAddress(slaveAddr) || master_state != MASTER_STATE_READ_READY)
{
I2C_HAL_SendStop(instance);
I2C_HAL_SetDirMode(instance, kI2CReceive);
return 0;
}
master_send_stop = sendStop;
master_state = MASTER_STATE_IDLE;
I2C_HAL_SetDirMode(instance, kI2CReceive);
/* Send NAK if only one byte to read. */
if (rxBufferQuantity == 0x1U)
{
I2C_HAL_SendNak(instance);
}
else
{
I2C_HAL_SendAck(instance);
}
I2C_HAL_ReadByte(instance);
t0 = millis();
while(master_state == MASTER_STATE_IDLE)
{
if(millis() - t0 >= 25)
{
rxBufferIndex = 0;
rxBufferLength = 0;
I2C_HAL_SendStop(instance);
I2C_HAL_SetDirMode(instance, kI2CReceive);
return 0; //timeout
}
}
if(master_state == MASTER_STATE_COMPLETE)
{
rxBufferIndex = 0;
return rxBufferLength;
}
else
{
rxBufferIndex = 0;
rxBufferLength = 0;
rxBufferQuantity = 0;
I2C_HAL_SendStop(instance);
I2C_HAL_SetDirMode(instance, kI2CReceive);
return 0; //timeout
}
}
/*FUNCTION**********************************************************************
*
* Function Name : I2C_HAL_MasterReceiveDataPolling
* Description : Performs a polling receive transaction on the I2C bus.
*
*END*/
i2c_status_t I2C_HAL_MasterReceiveDataPolling(I2C_Type * base,
uint16_t slaveAddr,
const uint8_t * cmdBuff,
uint32_t cmdSize,
uint8_t * rxBuff,
uint32_t rxSize)
{
int32_t i;
uint8_t directionBit, address;
/** Return if current I2C is already set as master. */
if (I2C_BRD_C1_MST(base))
{
return kStatus_I2C_Busy;
}
/** Get r/w bit according to CMD buffer setting
* read is 1, write is 0. */
directionBit = (cmdBuff) ? 0x0U : 0x1U;
address = (uint8_t)slaveAddr << 1U;
/** Set direction to send */
I2C_HAL_SetDirMode(base, kI2CSend);
/** Generate START signal. */
I2C_HAL_SendStart(base);
/** Send slave address */
if (!I2C_HAL_WriteByteBlocking(base, address | directionBit))
{
/** Send STOP if no ACK received */
I2C_HAL_SendStop(base);
return kStatus_I2C_ReceivedNak;
}
/** Send CMD buffer */
if (cmdBuff != NULL)
{
while (cmdSize--)
{
if (!I2C_HAL_WriteByteBlocking(base, *cmdBuff--))
{
/** Send STOP if no ACK received */
I2C_HAL_SendStop(base);
return kStatus_I2C_ReceivedNak;
}
}
/** Need to generate a repeat start before changing to receive. */
I2C_HAL_SendStart(base);
/** Send slave address again */
if (!I2C_HAL_WriteByteBlocking(base, address | 1U))
{
/** Send STOP if no ACK received */
I2C_HAL_SendStop(base);
return kStatus_I2C_ReceivedNak;
}
}
/** Change direction to receive. */
I2C_HAL_SetDirMode(base, kI2CReceive);
/** Send NAK if only one byte to read. */
if (rxSize == 0x1U)
{
I2C_HAL_SendNak(base);
}
else
{
I2C_HAL_SendAck(base);
}
/** Dummy read to trigger receive of next byte. */
I2C_HAL_ReadByteBlocking(base);
/** Receive data */
for(i=rxSize-1; i>=0; i--)
{
switch (i)
{
case 0x0U:
/** Generate STOP signal. */
I2C_HAL_SendStop(base);
break;
case 0x1U:
/** For the byte before last, we need to set NAK */
I2C_HAL_SendNak(base);
break;
default :
I2C_HAL_SendAck(base);
break;
}
/** Read recently received byte into buffer and update buffer index */
if (i==0)
{
*rxBuff++ = I2C_HAL_ReadByte(base);
}
else
{
*rxBuff++ = I2C_HAL_ReadByteBlocking(base);
}
}
return kStatus_I2C_Success;
}
