/******************************************************************************
*
* This function sends the proper byte of the address as well as generate the
* proper address bit fields depending on the address byte required and the
* direction of the data (write or read).
*
* A master receiving has the restriction that the direction must be switched
* from write to read when the third address byte is transmitted.
* For the last byte of the 10 bit address, repeated start must be set prior
* to writing the address. If repeated start options is enabled, the
* control register is written before the address is written to the Tx reg.
*
* @param InstancePtr is a pointer to the XIic instance to be worked on.
*
* @return None.
*
* @note
*
* This function does read/modify/write to the device control register. Calling
* functions must ensure critical sections are used.
*
******************************************************************************/
static void SendSlaveAddr(XIic *InstancePtr)
{
u32 CRreg;
/*
* Set the control register for Master Receive, repeated start must be
* set before writing the address, MSMS should be already set, don't
* set here so if arbitration is lost or some other reason we don't
* want MSMS set incase of error.
*/
CRreg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
CRreg |= XIIC_CR_REPEATED_START_MASK;
CRreg &= ~XIIC_CR_DIR_IS_TX_MASK;
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET, CRreg);
/*
* Send the 1st byte of the 10 bit address as a read operation, enable
* the receive interrupt to know when data is received, assuming that
* the receive FIFO threshold has been previously set.
*/
XIic_Send10BitAddrByte1(InstancePtr->AddrOfSlave, XIIC_READ_OPERATION);
XIic_ClearEnableIntr(InstancePtr->BaseAddress, XIIC_INTR_RX_FULL_MASK);
}
/*****************************************************************************
*
* This function checks to see if the IIC bus is busy. If so, it will enable
* the bus not busy interrupt such that the driver is notified when the bus
* is no longer busy.
*
* @param InstancePtr points to the Iic instance to be worked on.
*
* @return
* - FALSE indicates the IIC bus is not busy.
* - TRUE indicates the bus was in use and that the BusNotBusy
* interrupt is enabled which will update the EventStatus when
* the bus is no longer busy.
*
* @note None.
*
******************************************************************************/
static int IsBusBusy(XIic *InstancePtr)
{
u32 CntlReg;
u32 StatusReg;
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
StatusReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_SR_REG_OFFSET);
/*
* If this device is already master of the bus as when using the
* repeated start and the bus is busy setup to wait for it to not be
* busy.
*/
if (((CntlReg & XIIC_CR_MSMS_MASK) == 0) && /* Not master */
(StatusReg & XIIC_SR_BUS_BUSY_MASK)) { /* Is busy */
/*
* The bus is busy, clear pending BNB interrupt incase
* previously set and then enable BusNotBusy interrupt.
*/
InstancePtr->BNBOnly = TRUE;
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_BNB_MASK);
InstancePtr->Stats.BusBusy++;
return TRUE;
}
return FALSE;
}
/**
*
* This function sends data as a slave on the IIC bus and should not be called
* until an event has occurred that indicates the device has been selected by
* a master attempting read from the slave (XII_MASTER_READ_EVENT).
*
* @param InstancePtr is a pointer to the XIic instance to be worked on.
* @param TxMsgPtr is a pointer to the data to be transmitted.
* @param ByteCount is the number of message bytes to be sent.
*
* @return
* - XST_SUCCESS indicates the message transmission has been
* initiated.
* - XST_IIC_NOT_SLAVE indicates the device has not been
* selected to be a slave on the IIC bus such that data
* cannot be sent.
*
* @note None.
*
******************************************************************************/
int XIic_SlaveSend(XIic *InstancePtr, u8 *TxMsgPtr, int ByteCount)
{
u32 IntrStatus;
u32 Status;
/*
* If the device is not a slave on the IIC bus then indicate an error
* because data cannot be sent on the bus.
*/
Status = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_SR_REG_OFFSET);
if ((Status & XIIC_SR_ADDR_AS_SLAVE_MASK) == 0) {
return XST_IIC_NOT_SLAVE;
}
XIic_IntrGlobalDisable(InstancePtr->BaseAddress);
/*
* Save message state and invalidate the receive buffer pointer to
* indicate the direction of transfer is sending.
*/
InstancePtr->SendByteCount = ByteCount;
InstancePtr->SendBufferPtr = TxMsgPtr;
InstancePtr->RecvBufferPtr = NULL;
/*
* Start sending the specified data and then interrupt processing will
* complete it.
*/
XIic_TransmitFifoFill(InstancePtr, XIIC_SLAVE_ROLE);
/* Clear any pending Tx empty, Tx Error and interrupt then enable them.
* The Tx error interrupt indicates when the message is complete.
* If data remaining to be sent, clear and enable Tx ½ empty interrupt.
*/
IntrStatus = (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK);
if (InstancePtr->SendByteCount > 1) {
IntrStatus |= XIIC_INTR_TX_HALF_MASK;
}
/*
* Clear the interrupts in the status and then enable them and then
* exit the critical region.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress, IntrStatus);
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
/**
*
* This function starts the IIC device and driver by enabling the proper
* interrupts such that data may be sent and received on the IIC bus.
* This function must be called before the functions to send and receive data.
*
* Before XIic_Start() is called, the interrupt control must connect the ISR
* routine to the interrupt handler. This is done by the user, and not
* XIic_Start() to allow the user to use an interrupt controller of their choice.
*
* Start enables:
* - IIC device
* - Interrupts:
* - Addressed as slave to allow messages from another master
* - Arbitration Lost to detect Tx arbitration errors
* - Global IIC interrupt
*
* @param InstancePtr is a pointer to the XIic instance to be worked on.
*
* @return XST_SUCCESS always.
*
* @note
*
* The device interrupt is connected to the interrupt controller, but no
* "messaging" interrupts are enabled. Addressed as Slave is enabled to
* reception of messages when this devices address is written to the bus.
* The correct messaging interrupts are enabled when sending or receiving
* via the IicSend() and IicRecv() functions. No action is required
* by the user to control any IIC interrupts as the driver completely
* manages all 8 interrupts. Start and Stop control the ability
* to use the device. Stopping the device completely stops all device
* interrupts from the processor.
*
****************************************************************************/
int XIic_Start(XIic *InstancePtr)
{
Xil_AssertNonvoid(InstancePtr != NULL);
Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
/*
* Mask off all interrupts, each is enabled when needed.
*/
XIic_WriteIier(InstancePtr->BaseAddress, 0);
/*
* Clear all interrupts by reading and rewriting exact value back.
* Only those bits set will get written as 1 (writing 1 clears intr).
*/
XIic_ClearIntr(InstancePtr->BaseAddress, 0xFFFFFFFF);
/*
* Enable the device.
*/
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
XIIC_CR_ENABLE_DEVICE_MASK);
/*
* Set Rx FIFO Occupancy depth to throttle at
* first byte(after reset = 0).
*/
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_RFD_REG_OFFSET, 0);
/*
* Clear and enable the interrupts needed.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_AAS_MASK | XIIC_INTR_ARB_LOST_MASK);
InstancePtr->IsStarted = XIL_COMPONENT_IS_STARTED;
InstancePtr->IsDynamic = FALSE;
/*
* Enable the Global interrupt enable.
*/
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
/**
*
* This function is called when the IIC device is Addressed As a Slave (AAS).
* This occurs when another device on the bus, a master, has addressed this
* device to receive a message.
*
* @param InstancePtr is a pointer to the XIic instance to be worked on.
*
* @return None.
*
* @note None.
*
******************************************************************************/
static void AddrAsSlaveHandler(XIic *InstancePtr)
{
u32 Status;
int CallValue;
/*
* Disable AAS interrupt to clear the interrupt condition since this is
* interrupt does not go away and enable the not addressed as a slave
* interrrupt to tell when the master stops data transfer.
*/
XIic_DisableIntr(InstancePtr->BaseAddress, XIIC_INTR_AAS_MASK);
XIic_ClearEnableIntr(InstancePtr->BaseAddress, XIIC_INTR_NAAS_MASK);
/*
* Determine how the slave is being addressed and call the handler to
* notify the user of the event.
*/
Status = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_SR_REG_OFFSET);
/*
* Determine if the master is trying to perform a read or write
* operation.
*/
if (Status & XIIC_SR_MSTR_RDING_SLAVE_MASK) {
CallValue = XII_MASTER_READ_EVENT;
} else {
CallValue = XII_MASTER_WRITE_EVENT;
}
/*
* If being addressed with general call also indicate to handler.
*/
if (Status & XIIC_SR_GEN_CALL_MASK) {
CallValue |= XII_GENERAL_CALL_EVENT;
}
InstancePtr->StatusHandler(InstancePtr->StatusCallBackRef, CallValue);
return;
}
/**
* This function receives data as a master from a slave device on the IIC bus.
* If the bus is busy, it will indicate so and then enable an interrupt such
* that the status handler will be called when the bus is no longer busy. The
* slave address which has been set with the XIic_SetAddress() function is the
* address from which data is received. Receiving data on the bus performs a
* read operation.
*
* @param InstancePtr is a pointer to the Iic instance to be worked on.
* @param RxMsgPtr is a pointer to the data to be transmitted
* @param ByteCount is the number of message bytes to be sent
*
* @return
* - XST_SUCCESS indicates the message reception processes has
* been initiated.
* - XST_IIC_BUS_BUSY indicates the bus was in use and that the
* BusNotBusy interrupt is enabled which will update the
* EventStatus when the bus is no longer busy.
* - XST_IIC_GENERAL_CALL_ADDRESS indicates the slave address
* is set to the the general call address. This is not allowed
* for Master receive mode.
*
* @internal
*
* The receive FIFO threshold is a zero based count such that 1 must be
* subtracted from the desired count to get the correct value. When receiving
* data it is also necessary to not receive the last byte with the prior bytes
* because the acknowledge must be setup before the last byte is received.
*
******************************************************************************/
int XIic_MasterRecv(XIic *InstancePtr, u8 *RxMsgPtr, int ByteCount)
{
u32 CntlReg;
u8 Temp;
/*
* If the slave address is zero (general call) the master can't perform
* receive operations, indicate an error.
*/
if (InstancePtr->AddrOfSlave == 0) {
return XST_IIC_GENERAL_CALL_ADDRESS;
}
XIic_IntrGlobalDisable(InstancePtr->BaseAddress);
/*
* Ensure that the master processing has been included such that events
* will be properly handled.
*/
XIIC_MASTER_INCLUDE;
InstancePtr->IsDynamic = FALSE;
/*
* If the busy is busy, then exit the critical region and wait for the
* bus to not be busy, the function enables the bus not busy interrupt.
*/
if (IsBusBusy(InstancePtr)) {
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_IIC_BUS_BUSY;
}
/*
* Save message state for event driven processing.
*/
InstancePtr->RecvByteCount = ByteCount;
InstancePtr->RecvBufferPtr = RxMsgPtr;
/*
* Clear and enable Rx full interrupt if using 7 bit, If 10 bit, wait
* until last address byte sent incase arbitration gets lost while
* sending out address.
*/
if ((InstancePtr->Options & XII_SEND_10_BIT_OPTION) == 0) {
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_RX_FULL_MASK);
}
/*
* If already a master on the bus, the direction was set by Rx Interrupt
* routine to Tx which is throttling bus because during Rxing, Tx reg is
* empty = throttle. CR needs setting before putting data or the address
* written will go out as Tx instead of receive. Start Master Rx by
* setting CR Bits MSMS to Master and msg direction.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if (CntlReg & XIIC_CR_MSMS_MASK) {
CntlReg |= XIIC_CR_REPEATED_START_MASK;
XIic_SetControlRegister(InstancePtr, CntlReg, ByteCount);
InstancePtr->Stats.RepeatedStarts++;
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
}
/*
* Set receive FIFO occupancy depth which must be done prior to writing
* the address in the FIFO because the transmitter will immediatedly
* start when in repeated start mode followed by the receiver such that
* the number of bytes to receive should be set 1st.
*/
if (ByteCount == 1) {
Temp = 0;
} else {
if (ByteCount <= IIC_RX_FIFO_DEPTH) {
Temp = ByteCount - 2;
} else {
Temp = IIC_RX_FIFO_DEPTH - 1;
}
}
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_RFD_REG_OFFSET,
(u32) Temp);
if (InstancePtr->Options & XII_SEND_10_BIT_OPTION) {
/*
* Send the 1st and 2nd byte of the 10 bit address of a write
* operation, write because it's a 10 bit address.
*/
XIic_Send10BitAddrByte1(InstancePtr->AddrOfSlave,
XIIC_WRITE_OPERATION);
XIic_Send10BitAddrByte2(InstancePtr->AddrOfSlave);
/*
* Set flag to indicate the next byte of the address needs to be
* send, clear and enable Tx empty interrupt.
*/
InstancePtr->TxAddrMode = XIIC_TX_ADDR_MSTR_RECV_MASK;
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_EMPTY_MASK);
} else {
/*
* 7 bit slave address, send the address for a read operation
* and set the state to indicate the address has been sent.
*/
XIic_Send7BitAddr(InstancePtr->AddrOfSlave,
XIIC_READ_OPERATION);
InstancePtr->TxAddrMode = XIIC_TX_ADDR_SENT;
}
/*
* Tx error is enabled incase the address (7 or 10) has no device to
* answer with Ack. When only one byte of data, must set NO ACK before
* address goes out therefore Tx error must not be enabled as it will
* go off immediately and the Rx full interrupt will be checked.
* If full, then the one byte was received and the Tx error will be
* disabled without sending an error callback msg.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_ERROR_MASK);
/*
* When repeated start not used, MSMS gets set after putting data
* in Tx reg. Start Master Rx by setting CR Bits MSMS to Master and
* msg direction.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if ((CntlReg & XIIC_CR_MSMS_MASK) == 0) {
CntlReg |= XIIC_CR_MSMS_MASK;
XIic_SetControlRegister(InstancePtr, CntlReg, ByteCount);
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
}
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
/**
* This function sends data as a master on the IIC bus. If the bus is busy, it
* will indicate so and then enable an interrupt such that the status handler
* will be called when the bus is no longer busy. The slave address which has
* been set with the XIic_SetAddress() function is the address to which the
* specific data is sent. Sending data on the bus performs a write operation.
*
* @param InstancePtr points to the Iic instance to be worked on.
* @param TxMsgPtr points to the data to be transmitted.
* @param ByteCount is the number of message bytes to be sent.
*
* @return
* - XST_SUCCESS indicates the message transmission has been
* initiated.
* - XST_IIC_BUS_BUSY indicates the bus was in use and that
* the BusNotBusy interrupt is enabled which will update the
* EventStatus when the bus is no longer busy.
*
* @note None.
*
******************************************************************************/
int XIic_MasterSend(XIic *InstancePtr, u8 *TxMsgPtr, int ByteCount)
{
u32 CntlReg;
XIic_IntrGlobalDisable(InstancePtr->BaseAddress);
/*
* Ensure that the master processing has been included such that events
* will be properly handled.
*/
XIIC_MASTER_INCLUDE;
InstancePtr->IsDynamic = FALSE;
/*
* If the busy is busy, then exit the critical region and wait for the
* bus to not be busy, the function enables the bus not busy interrupt.
*/
if (IsBusBusy(InstancePtr)) {
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_IIC_BUS_BUSY;
}
/*
* If it is already a master on the bus (repeated start), the direction
* was set to Tx which is throttling bus. The control register needs to
* be set before putting data into the FIFO.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if (CntlReg & XIIC_CR_MSMS_MASK) {
CntlReg &= ~XIIC_CR_NO_ACK_MASK;
CntlReg |= (XIIC_CR_DIR_IS_TX_MASK |
XIIC_CR_REPEATED_START_MASK);
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
InstancePtr->Stats.RepeatedStarts++;
}
/*
* Save message state.
*/
InstancePtr->SendByteCount = ByteCount;
InstancePtr->SendBufferPtr = TxMsgPtr;
/*
* Put the address into the FIFO to be sent and indicate that the
* operation to be performed on the bus is a write operation,
* a general call address is handled the same as a 7 bit address even
* if 10 bit address is selected.
* Set the transmit address state to indicate the address has been sent.
*/
if ((InstancePtr->Options & XII_SEND_10_BIT_OPTION) &&
(InstancePtr->AddrOfSlave != 0)) {
XIic_Send10BitAddrByte1(InstancePtr->AddrOfSlave,
XIIC_WRITE_OPERATION);
XIic_Send10BitAddrByte2(InstancePtr->AddrOfSlave);
} else {
XIic_Send7BitAddr(InstancePtr->AddrOfSlave,
XIIC_WRITE_OPERATION);
}
/*
* Set the transmit address state to indicate the address has been sent
* for communication with event driven processing.
*/
InstancePtr->TxAddrMode = XIIC_TX_ADDR_SENT;
/*
* Fill remaining available FIFO with message data.
*/
if (InstancePtr->SendByteCount > 1) {
XIic_TransmitFifoFill(InstancePtr, XIIC_MASTER_ROLE);
}
/*
* After filling fifo, if data yet to send > 1, enable Tx ½ empty
* interrupt.
*/
if (InstancePtr->SendByteCount > 1) {
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_HALF_MASK);
}
/*
* Clear any pending Tx empty, Tx Error and then enable them.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_ERROR_MASK |
XIIC_INTR_TX_EMPTY_MASK);
/*
* When repeated start not used, MSMS must be set after putting data
* into transmit FIFO, start the transmitter.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if ((CntlReg & XIIC_CR_MSMS_MASK) == 0) {
CntlReg &= ~XIIC_CR_NO_ACK_MASK;
CntlReg |= XIIC_CR_MSMS_MASK | XIIC_CR_DIR_IS_TX_MASK;
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
}
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
/**
*
* This function is called when the IIC device receives Not Addressed As Slave
* (NAAS) interrupt which indicates that the master has released the bus implying
* a data transfer is complete.
*
* @param InstancePtr is a pointer to the XIic instance to be worked on.
*
* @return None.
*
* @note None.
*
******************************************************************************/
static void NotAddrAsSlaveHandler(XIic *InstancePtr)
{
u32 Status;
u32 CntlReg;
u8 BytesToRead;
u8 LoopCnt;
/*
* Disable NAAS so that the condition will not continue to interrupt
* and enable the addressed as slave interrupt to know when a master
* selects a slave on the bus.
*/
XIic_DisableIntr(InstancePtr->BaseAddress, XIIC_INTR_NAAS_MASK);
XIic_ClearEnableIntr(InstancePtr->BaseAddress, XIIC_INTR_AAS_MASK);
/*
* Flush Tx FIFO by toggling TxFIFOResetBit. FIFO runs normally at 0
* Do this incase needed to Tx FIFO with more than expected if what
* was set to Tx was less than what the Master expected - read more
* from this slave so FIFO had junk in it.
*/
XIic_FlushTxFifo(InstancePtr);
/*
* NAAS interrupt was asserted but received data in recieve FIFO is
* less than Rc_FIFO_PIRQ to assert an receive full interrupt,in this
* condition as data recieved is valid we have to read data before FIFO
* flush.
*/
Status = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_SR_REG_OFFSET);
if (!(Status & XIIC_SR_RX_FIFO_EMPTY_MASK))
{
BytesToRead = (XIic_ReadReg(InstancePtr->BaseAddress,
XIIC_RFO_REG_OFFSET)) + 1;
if (InstancePtr->RecvByteCount > BytesToRead) {
for (LoopCnt = 0; LoopCnt < BytesToRead; LoopCnt++) {
XIic_ReadRecvByte(InstancePtr);
}
}
}
InstancePtr->RecvByteCount = 0;
/*
* Flush Rx FIFO should slave Rx had a problem, sent No ack but
* still received a few bytes. Should the slave receive have disabled
* acknowledgement, clear Rx FIFO.
*/
XIic_FlushRxFifo(InstancePtr);
/*
* Set FIFO occupancy depth = 1 so that the first byte will throttle
* next recieve msg.
*/
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_RFD_REG_OFFSET, 0);
/*
* Should the slave receive have disabled acknowledgement,
* enable to allow acknowledgment for receipt of our address to
* again be used as a slave.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
(CntlReg & ~XIIC_CR_NO_ACK_MASK));
/*
* Which callback depends on messaging direction, the buffer pointer NOT
* being used indicates the direction of data transfer.
*/
Status = XIic_ReadIier(InstancePtr->BaseAddress);
if (InstancePtr->RecvBufferPtr == NULL) {
/*
* Slave was sending data so disable all transmit interrupts and
* call the callback handler to indicate the transfer is
* complete.
*/
XIic_WriteIier(InstancePtr->BaseAddress,
(Status & ~XIIC_TX_INTERRUPTS));
InstancePtr->SendHandler(InstancePtr->SendCallBackRef,
InstancePtr->SendByteCount);
}
else {
/*
* Slave was receiving data so disable receive full interrupt
* and call the callback handler to notify the transfer is
* complete.
*/
XIic_WriteIier(InstancePtr->BaseAddress,
(Status & ~XIIC_INTR_RX_FULL_MASK));
InstancePtr->RecvHandler(InstancePtr->RecvCallBackRef,
InstancePtr->RecvByteCount);
}
return;
}
/**
* This function receives data as a master from a slave device on the IIC bus.
* If the bus is busy, it will indicate so and then enable an interrupt such
* that the status handler will be called when the bus is no longer busy. The
* slave address which has been set with the XIic_SetAddress() function is the
* address from which data is received. Receiving data on the bus performs a
* read operation.
*
* @param InstancePtr is a pointer to the Iic instance to be worked on.
* @param RxMsgPtr is a pointer to the data to be transmitted.
* @param ByteCount is the number of message bytes to be sent.
*
* @return - XST_SUCCESS indicates the message reception processes has been
* initiated.
* - XST_IIC_BUS_BUSY indicates the bus was in use and that the
* BusNotBusy interrupt is enabled which will update the
* EventStatus when the bus is no longer busy.
* - XST_IIC_GENERAL_CALL_ADDRESS indicates the slave address is
* set to the general call address. This is not allowed for Master
* receive mode.
*
* @note The receive FIFO threshold is a zero based count such that 1
* must be subtracted from the desired count to get the correct
* value. When receiving data it is also necessary to not receive
* the last byte with the prior bytes because the acknowledge must
* be setup before the last byte is received.
*
******************************************************************************/
int XIic_DynMasterRecv(XIic *InstancePtr, u8 *RxMsgPtr, u8 ByteCount)
{
u32 CntlReg;
u32 RxFifoOccy;
/*
* If the slave address is zero (general call) the master can't perform
* receive operations, indicate an error.
*/
if (InstancePtr->AddrOfSlave == 0) {
return XST_IIC_GENERAL_CALL_ADDRESS;
}
/*
* Disable the Interrupts.
*/
XIic_IntrGlobalDisable(InstancePtr->BaseAddress);
/*
* Ensure that the master processing has been included such that events
* will be properly handled.
*/
XIIC_DYN_MASTER_INCLUDE;
InstancePtr->IsDynamic = TRUE;
/*
* If the busy is busy, then exit the critical region and wait for the
* bus to not be busy, the function enables the bus not busy interrupt.
*/
if (IsBusBusy(InstancePtr)) {
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_IIC_BUS_BUSY;
}
/*
* Save message state for event driven processing.
*/
InstancePtr->RecvByteCount = ByteCount;
InstancePtr->RecvBufferPtr = RxMsgPtr;
/*
* Clear and enable Rx full interrupt.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress, XIIC_INTR_RX_FULL_MASK);
/*
* If already a master on the bus, the direction was set by Rx Interrupt
* routine to Tx which is throttling bus because during Rxing, Tx reg is
* empty = throttle. CR needs setting before putting data or the address
* written will go out as Tx instead of receive. Start Master Rx by
* setting CR Bits MSMS to Master and msg direction.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if (CntlReg & XIIC_CR_MSMS_MASK) {
/*
* Set the Repeated Start bit in CR.
*/
CntlReg |= XIIC_CR_REPEATED_START_MASK;
XIic_SetControlRegister(InstancePtr, CntlReg, ByteCount);
/*
* Increment stats counts.
*/
InstancePtr->Stats.RepeatedStarts++;
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
}
/*
* Set receive FIFO occupancy depth which must be done prior to writing
* the address in the FIFO because the transmitter will immediately
* start when in repeated start mode followed by the receiver such
* that the number of bytes to receive should be set 1st.
*/
if (ByteCount == 1) {
RxFifoOccy = 0;
}
else {
if (ByteCount <= IIC_RX_FIFO_DEPTH) {
RxFifoOccy = ByteCount - 2;
} else {
RxFifoOccy = IIC_RX_FIFO_DEPTH - 1;
}
}
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_RFD_REG_OFFSET,
RxFifoOccy);
/*
* Send the Seven Bit address. Only 7 bit addressing is supported in
* Dynamic mode and mark that the address has been sent.
*/
XIic_DynSend7BitAddress(InstancePtr->BaseAddress,
InstancePtr->AddrOfSlave, XIIC_READ_OPERATION);
InstancePtr->TxAddrMode = XIIC_TX_ADDR_SENT;
/*
* Send the bytecount to be received and set the stop bit.
*/
XIic_DynSendStop(InstancePtr->BaseAddress, ByteCount);
/*
* Tx error is enabled incase the address has no device to answer
* with Ack. When only one byte of data, must set NO ACK before address
* goes out therefore Tx error must not be enabled as it will go off
* immediately and the Rx full interrupt will be checked. If full, then
* the one byte was received and the Tx error will be disabled without
* sending an error callback msg.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_ERROR_MASK);
/*
* Enable the Interrupts.
*/
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
/**
* This function sends data as a Dynamic master on the IIC bus. If the bus is
* busy, it will indicate so and then enable an interrupt such that the status
* handler will be called when the bus is no longer busy. The slave address is
* sent by using XIic_DynSend7BitAddress().
*
* @param InstancePtr points to the Iic instance to be worked on.
* @param TxMsgPtr points to the data to be transmitted.
* @param ByteCount is the number of message bytes to be sent.
*
* @return XST_SUCCESS if successful else XST_FAILURE.
*
* @note None.
*
******************************************************************************/
int XIic_DynMasterSend(XIic *InstancePtr, u8 *TxMsgPtr, u8 ByteCount)
{
u32 CntlReg;
XIic_IntrGlobalDisable(InstancePtr->BaseAddress);
/*
* Ensure that the Dynamic master processing has been included such that
* events will be properly handled.
*/
XIIC_DYN_MASTER_INCLUDE;
InstancePtr->IsDynamic = TRUE;
/*
* If the busy is busy, then exit the critical region and wait for the
* bus not to be busy. The function enables the BusNotBusy interrupt.
*/
if (IsBusBusy(InstancePtr)) {
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_FAILURE;
}
/*
* If it is already a master on the bus (repeated start), the direction
* was set to Tx which is throttling bus. The control register needs to
* be set before putting data into the FIFO.
*/
CntlReg = XIic_ReadReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET);
if (CntlReg & XIIC_CR_MSMS_MASK) {
CntlReg &= ~XIIC_CR_NO_ACK_MASK;
CntlReg |= XIIC_CR_DIR_IS_TX_MASK;
XIic_WriteReg(InstancePtr->BaseAddress, XIIC_CR_REG_OFFSET,
CntlReg);
InstancePtr->Stats.RepeatedStarts++;
}
/*
* Save message state.
*/
InstancePtr->SendByteCount = ByteCount;
InstancePtr->SendBufferPtr = TxMsgPtr;
/*
* Send the Seven Bit address. Only 7 bit addressing is supported in
* Dynamic mode.
*/
XIic_DynSend7BitAddress(InstancePtr->BaseAddress,
InstancePtr->AddrOfSlave,
XIIC_WRITE_OPERATION);
/*
* Set the transmit address state to indicate the address has been sent
* for communication with event driven processing.
*/
InstancePtr->TxAddrMode = XIIC_TX_ADDR_SENT;
/*
* Fill the Tx FIFO.
*/
if (InstancePtr->SendByteCount > 1) {
XIic_TransmitFifoFill(InstancePtr, XIIC_MASTER_ROLE);
}
/*
* After filling fifo, if data yet to send > 1, enable Tx ½ empty
* interrupt.
*/
if (InstancePtr->SendByteCount > 1) {
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_HALF_MASK);
}
/*
* Clear any pending Tx empty, Tx Error and then enable them.
*/
XIic_ClearEnableIntr(InstancePtr->BaseAddress,
XIIC_INTR_TX_ERROR_MASK |
XIIC_INTR_TX_EMPTY_MASK);
/*
* Enable the Interrupts.
*/
XIic_IntrGlobalEnable(InstancePtr->BaseAddress);
return XST_SUCCESS;
}
