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/******************************************************************************
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/*****************************************************************************/
/**
* @file xiic_slave_example.c
*
* This file consists of a Interrupt mode design example which uses the Xilinx
* IIC device and XIic driver to exercise the slave functionality of the IIC
* device.
*
* The XIic_SlaveSend() API is used to transmit the data and
* XIic_SlaveRecv() API is used to receive the data.
*
* The example is tested on ML300/ML310/ML403/ML501 Xilinx boards.
*
* The IIC devices that are present on the Xilinx boards donot support the Master
* functionality. This example has been tested with an off board external IIC
* Master device and the IIC device configured as a Slave.
*
* This code assumes that no Operating System is being used.
*
* @note
*
* None.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date	 Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a mta  03/01/06 Created.
* 2.00a ktn  11/17/09 Updated to use the HAL APIs and replaced call to
*		      XIic_Initialize API with XIic_LookupConfig and
*		      XIic_CfgInitialize. Some of the macros have been
*		      renamed in the IIC driver and some renamed macros are
*		      used in this example.
* </pre>
*
******************************************************************************/
 
/***************************** Include Files *********************************/
 
#include "xparameters.h"
#include "xiic.h"
#include "xintc.h"
#include "xil_exception.h"
 
/************************** Constant Definitions *****************************/
 
/*
 * The following constants map to the XPAR parameters created in the
 * xparameters.h file. They are defined here such that a user can easily
 * change all the needed parameters in one place.
 */
#define IIC_DEVICE_ID		XPAR_IIC_0_DEVICE_ID
#define INTC_DEVICE_ID		XPAR_INTC_0_DEVICE_ID
#define IIC_INTR_ID		XPAR_INTC_0_IIC_0_VEC_ID
 
/*
 * The following constant defines the address of the IIC device on the IIC bus.
 * Since the address is only 7 bits, this constant is the address divided by 2.
 */
#define SLAVE_ADDRESS		0x70	/* 0xE0 as an 8 bit number. */
 
#define RECEIVE_COUNT		25
#define SEND_COUNT		25
 
 
/**************************** Type Definitions *******************************/
 
/***************** Macros (Inline Functions) Definitions *********************/
 
/************************** Function Prototypes ******************************/
 
int IicSlaveExample();
int SlaveWriteData(u16 ByteCount);
int SlaveReadData(u8 *BufferPtr, u16 ByteCount);
static int SetupInterruptSystem(XIic * IicInstPtr);
static void StatusHandler(XIic *InstancePtr, int Event);
static void SendHandler(XIic *InstancePtr);
static void ReceiveHandler(XIic *InstancePtr);
 
/************************** Variable Definitions *****************************/
 
XIic IicInstance;		/* The instance of the IIC device. */
XIntc InterruptController;	/* The instance of the Interrupt Controller */
 
 
u8 WriteBuffer[SEND_COUNT];	/* Write buffer for writing a page. */
u8 ReadBuffer[RECEIVE_COUNT];	/* Read buffer for reading a page. */
 
volatile u8 TransmitComplete;
volatile u8 ReceiveComplete;
 
volatile u8 SlaveRead;
volatile u8 SlaveWrite;
 
/************************** Function Definitions *****************************/
 
/*****************************************************************************/
/**
* Main function to call the IIC Slave example.
*
* @param	None.
*
* @return	XST_SUCCESS if successful else XST_FAILURE.
*
* @note		None.
*
******************************************************************************/
int main(void)
{
	int Status;
 
	/*
	 * Run the IIC Slave example.
	 */
	Status = IicSlaveExample();
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	return XST_SUCCESS;
}
 
/*****************************************************************************/
/**
* This function writes and reads the data as a slave. The IIC master on the bus
* initiates the transfers.
*
* @param	None.
*
* @return	XST_SUCCESS if successful else XST_FAILURE.
*
* @note		None.
*
******************************************************************************/
int IicSlaveExample()
{
	int Status;
	u8 Index;
	XIic_Config *ConfigPtr;	/* Pointer to configuration data */
 
 
	/*
	 * Initialize the IIC driver so that it is ready to use.
	 */
	ConfigPtr = XIic_LookupConfig(IIC_DEVICE_ID);
	if (ConfigPtr == NULL) {
		return XST_FAILURE;
	}
 
	Status = XIic_CfgInitialize(&IicInstance, ConfigPtr,
					ConfigPtr->BaseAddress);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Setup the Interrupt System.
	 */
	Status = SetupInterruptSystem(&IicInstance);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Include the Slave functions.
	 */
	XIic_SlaveInclude();
 
	/*
	 * Set the Transmit, Receive and Status Handlers.
	 */
	XIic_SetStatusHandler(&IicInstance, &IicInstance,
				  (XIic_StatusHandler) StatusHandler);
	XIic_SetSendHandler(&IicInstance, &IicInstance,
				(XIic_Handler) SendHandler);
	XIic_SetRecvHandler(&IicInstance, &IicInstance,
				(XIic_Handler) ReceiveHandler);
 
	/*
	 * Set the Address as a RESPOND type.
	 */
	Status = XIic_SetAddress(&IicInstance, XII_ADDR_TO_RESPOND_TYPE,
				 SLAVE_ADDRESS);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * The IIC Master on this bus should initiate the transfer
	 * and write data to the slave at this instance.
	 */
	SlaveReadData(ReadBuffer, RECEIVE_COUNT);
 
	for (Index = 0; Index < SEND_COUNT; Index++) {
		WriteBuffer[Index] = Index;
	}
 
	/*
	 * The IIC Master on this bus should initiate the transfer
	 * and read data from the slave.
	 */
	SlaveWriteData(SEND_COUNT);
 
	return XST_SUCCESS;
}
 
/*****************************************************************************/
/**
* This function reads a buffer of bytes  when the IIC Master on the bus writes
* data to the slave device.
*
* @param	BufferPtr contains the address of the data buffer to be filled.
* @param	ByteCount contains the number of bytes in the buffer to be read.
*
* @return	XST_SUCCESS if successful else XST_FAILURE.
*
* @note		None
*
******************************************************************************/
int SlaveReadData(u8 *BufferPtr, u16 ByteCount)
{
	int Status;
 
	/*
	 * Set the defaults.
	 */
	ReceiveComplete = 1;
 
	/*
	 * Start the IIC device.
	 */
	Status = XIic_Start(&IicInstance);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Set the Global Interrupt Enable.
	 */
	XIic_IntrGlobalEnable(IicInstance.BaseAddress);
 
	/*
	 * Wait for AAS interrupt and completion of data reception.
	 */
	while ((ReceiveComplete) || (XIic_IsIicBusy(&IicInstance) == TRUE)) {
		if (SlaveRead) {
			XIic_SlaveRecv(&IicInstance, ReadBuffer, RECEIVE_COUNT);
			SlaveRead = 0;
		}
	}
 
	/*
	 * Disable the Global Interrupt Enable.
	 */
	XIic_IntrGlobalDisable(IicInstance.BaseAddress);
 
	/*
	 * Stop the IIC device.
	 */
	Status = XIic_Stop(&IicInstance);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	return XST_SUCCESS;
}
 
/*****************************************************************************/
/**
* This function writes a buffer of bytes to the IIC bus when the IIC master
* initiates a read operation.
*
* @param	ByteCount contains the number of bytes in the buffer to be
*		written.
*
* @return	XST_SUCCESS if successful else XST_FAILURE.
*
* @note		None.
*
******************************************************************************/
int SlaveWriteData(u16 ByteCount)
{
	int Status;
 
	/*
	 * Set the defaults.
	 */
	TransmitComplete = 1;
 
	/*
	 * Start the IIC device.
	 */
	Status = XIic_Start(&IicInstance);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Set the Global Interrupt Enable.
	 */
	XIic_IntrGlobalEnable(IicInstance.BaseAddress);
 
	/*
	 * Wait for AAS interrupt and transmission to complete.
	 */
	while ((TransmitComplete) || (XIic_IsIicBusy(&IicInstance) == TRUE)) {
		if (SlaveWrite) {
			XIic_SlaveSend(&IicInstance, WriteBuffer, SEND_COUNT);
			SlaveWrite = 0;
		}
	}
 
	/*
	 * Disable the Global Interrupt Enable bit.
	 */
	XIic_IntrGlobalDisable(IicInstance.BaseAddress);
 
	/*
	 * Stop the IIC device.
	 */
	Status = XIic_Stop(&IicInstance);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	return XST_SUCCESS;
}
 
/****************************************************************************/
/**
* This Status handler is called asynchronously from an interrupt context and
* indicates the events that have occurred.
*
* @param	InstancePtr is not used, but contains a pointer to the IIC
* 		device driver instance which the handler is being called for.
* @param	Event indicates whether it is a request for a write or read.
*
* @return	None.
*
* @note		None.
*
****************************************************************************/
static void StatusHandler(XIic *InstancePtr, int Event)
{
	/*
	 * Check whether the Event is to write or read the data from the slave.
	 */
	if (Event == XII_MASTER_WRITE_EVENT) {
		/*
		 * Its a Write request from Master.
		 */
		SlaveRead = 1;
	} else {
		/*
		 * Its a Read request from the master.
		 */
		SlaveWrite = 1;
	}
}
 
/****************************************************************************/
/**
* This Send handler is called asynchronously from an interrupt
* context and indicates that data in the specified buffer has been sent.
*
* @param	InstancePtr is a pointer to the IIC driver instance for which
*		the handler is being called for.
*
* @return	None.
*
* @note		None.
*
****************************************************************************/
static void SendHandler(XIic *InstancePtr)
{
	TransmitComplete = 0;
}
 
/****************************************************************************/
/**
* This Receive handler is called asynchronously from an interrupt
* context and indicates that data in the specified buffer has been Received.
*
* @param	InstancePtr is a pointer to the IIC driver instance for which
* 		the handler is being called for.
*
* @return	None.
*
* @note		None.
*
****************************************************************************/
static void ReceiveHandler(XIic *InstancePtr)
{
	ReceiveComplete = 0;
}
 
/****************************************************************************/
/**
* This function setups the interrupt system so interrupts can occur for the
* IIC. The function is application-specific since the actual system may or
* may not have an interrupt controller. The IIC device could be directly
* connected to a processor without an interrupt controller. The user should
* modify this function to fit the application.
*
* @param	IicInstPtr contains a pointer to the instance of the IIC  which
*		is going to be connected to the interrupt controller.
*
* @return	XST_SUCCESS if successful else XST_FAILURE.
*
* @note		None.
*
****************************************************************************/
static int SetupInterruptSystem(XIic * IicInstPtr)
{
	int Status;
 
	if (InterruptController.IsStarted == XIL_COMPONENT_IS_STARTED) {
		return XST_SUCCESS;
	}
 
	/*
	 * Initialize the interrupt controller driver so that it's ready to use.
	 */
	Status = XIntc_Initialize(&InterruptController, INTC_DEVICE_ID);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Connect the device driver handler that will be called when an
	 * interrupt for the device occurs, the handler defined above
	 * performs the specific interrupt processing for the device.
	 */
	Status = XIntc_Connect(&InterruptController, IIC_INTR_ID,
				   (XInterruptHandler) XIic_InterruptHandler,
				   IicInstPtr);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Start the interrupt controller so interrupts are enabled for all
	 * devices that cause interrupts.
	 */
	Status = XIntc_Start(&InterruptController, XIN_REAL_MODE);
	if (Status != XST_SUCCESS) {
		return XST_FAILURE;
	}
 
	/*
	 * Enable the interrupts for the IIC device.
	 */
	XIntc_Enable(&InterruptController, IIC_INTR_ID);
 
	/*
	 * Initialize the exception table.
	 */
	Xil_ExceptionInit();
 
	/*
	 * Register the interrupt controller handler with the exception table.
	 */
	Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,
				 (Xil_ExceptionHandler) XIntc_InterruptHandler,
				 &InterruptController);
 
	/*
	 * Enable non-critical exceptions.
	 */
	Xil_ExceptionEnable();
 
 
	return XST_SUCCESS;
}