/******************************************************************************
*
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******************************************************************************/
/****************************************************************************/
/**
*
* @file xcan_polled_example.c
*
* Contains an example of how to use the XCan driver directly. The example here
* shows using the driver/device in polled mode.
*
* @note
*
*
* The Baud Rate Prescaler Register (BRPR) and Bit Timing Register (BTR)
* are setup such that CAN baud rate equals 40Kbps, assuming that the
* the CAN clock frequency is 24MHz. The user needs to modify these values
* based on the desired baud rate and the CAN clock frequency. For more
* information see the CAN 2.0A, CAN 2.0B, ISO 11898-1 specifications.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver Who Date Changes
* ----- ----- -------- -----------------------------------------------
* 1.00a xd 04/12/05 First release
* 2.00a ktn 10/22/09 Updated driver to use the HAL APIs/macros.
* The macros have been renamed to remove _m from the name.
* </pre>
*
******************************************************************************/
/***************************** Include Files *********************************/
#include "xcan.h"
#include "xparameters.h"
#include "xstatus.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 CAN_DEVICE_ID XPAR_CAN_0_DEVICE_ID
/*
* Maximum CAN frame length in words.
*/
#define XCAN_MAX_FRAME_SIZE_IN_WORDS (XCAN_MAX_FRAME_SIZE / sizeof(u32))
#define FRAME_DATA_LENGTH 8 /* Frame Data field length */
/*
* Message Id Constant.
*/
#define TEST_MESSAGE_ID 2650
/*
* The Baud Rate Prescaler Register (BRPR) and Bit Timing Register (BTR)
* are setup such that CAN baud rate equals 40Kbps, assuming that the
* the CAN clock frequency is 24MHz. The user needs to modify these values
* based on the desired baud rate and the CAN clock frequency. For more
* information see the CAN 2.0A, CAN 2.0B, ISO 11898-1 specifications.
*/
#define TEST_BRPR_BAUD_PRESCALAR 29
#define TEST_BTR_SYNCJUMPWIDTH 3
#define TEST_BTR_SECOND_TIMESEGMENT 2
#define TEST_BTR_FIRST_TIMESEGMENT 15
/**************************** Type Definitions *******************************/
/***************** Macros (Inline Functions) Definitions *********************/
/************************** Function Prototypes ******************************/
int XCanPolledExample(u16 DeviceId);
static int SendFrame(XCan *InstancePtr);
static int RecvFrame(XCan *InstancePtr);
/************************** Variable Definitions *****************************/
/*
* Buffers to hold frames to send and receive. These are declared as global so
* that they are not on the stack.
* These buffers need to be 32-bit aligned
*/
static u32 TxFrame[XCAN_MAX_FRAME_SIZE_IN_WORDS];
static u32 RxFrame[XCAN_MAX_FRAME_SIZE_IN_WORDS];
/* Driver instance */
static XCan Can;
/*****************************************************************************/
/**
*
* Main function to call the example. This function is not included if the
* example is generated from the TestAppGen test tool.
*
* @param None
*
* @return
* - XST_SUCCESS if the example has completed successfully.
* - XST_FAILURE if the example has failed.
*
* @note None
*
******************************************************************************/
#ifndef TESTAPP_GEN
int main(void)
{
/*
* Run the Can Polled example, specify the Device ID that is generated
* in xparameters.h .
*/
if (XCanPolledExample(CAN_DEVICE_ID)) {
return XST_FAILURE;
}
return XST_SUCCESS;
}
#endif
/*****************************************************************************/
/**
*
* The entry point for showing the XCan driver in polled mode. The example
* configures the device for internal loopback mode, then sends a Can
* frame, receives the same Can frame, and verifies the frame contents.
*
* @param DeviceId is the XPAR_CAN_<instance_num>_DEVICE_ID value from
* xparameters.h.
*
* @return
*
* XST_SUCCESS if successful, otherwise driver-specific error code.
*
* @note
*
* If the device is not working correctly, this function may enter an infinite
* loop and will never return to the caller.
*
******************************************************************************/
int XCanPolledExample(u16 DeviceId)
{
int Status;
/*
* Initialize the XCan driver.
*/
Status = XCan_Initialize(&Can, DeviceId);
if (Status != XST_SUCCESS) {
return Status;
}
/*
* Run self-test on the device, which verifies basic sanity of the
* device and the driver.
*/
Status = XCan_SelfTest(&Can);
if (Status != XST_SUCCESS) {
return Status;
}
/*
* Enter Configuration Mode so we can setup Baud Rate Prescaler
* Register (BRPR) and Bit Timing Register (BTR)
*/
XCan_EnterMode(&Can, XCAN_MODE_CONFIG);
while(XCan_GetMode(&Can) != XCAN_MODE_CONFIG);
/*
* Setup Baud Rate Prescaler Register (BRPR) and Bit Timing Register
* (BTR) such that CAN baud rate equals 40Kbps, given the CAN clock
* frequency equal to 24MHz.
*/
XCan_SetBaudRatePrescaler(&Can, TEST_BRPR_BAUD_PRESCALAR);
XCan_SetBitTiming(&Can, TEST_BTR_SYNCJUMPWIDTH,
TEST_BTR_SECOND_TIMESEGMENT,
TEST_BTR_FIRST_TIMESEGMENT);
/*
* Enter Loop Back Mode.
*/
XCan_EnterMode(&Can, XCAN_MODE_LOOPBACK);
while(XCan_GetMode(&Can) != XCAN_MODE_LOOPBACK);
/*
* Send a frame, receive the frame via the loopback and verify its
* contents.
*/
Status = SendFrame(&Can);
if (Status != XST_SUCCESS) {
return Status;
}
Status = RecvFrame(&Can);
return Status;
}
/*****************************************************************************/
/**
*
* Send a CAN frame.
*
* @param InstancePtr is a pointer to the driver instance
*
* @return XST_SUCCESS if successful, a driver-specific return code if not.
*
* @note
*
* This function waits until TX FIFO has room for at least one frame before
* sending a frame. So this function may block if the hardware is not built
* correctly.
*
******************************************************************************/
static int SendFrame(XCan *InstancePtr)
{
u8 *FramePtr;
int Index;
int Status;
/*
* Create correct values for Identifier and Data Length Code Register.
*/
TxFrame[0] = XCan_CreateIdValue(TEST_MESSAGE_ID, 0, 0, 0, 0);
TxFrame[1] = XCan_CreateDlcValue(FRAME_DATA_LENGTH);
/*
* Now fill in the data field with known values so we can verify them
* on receive.
*/
FramePtr = (u8 *)(&TxFrame[2]);
for (Index = 0; Index < FRAME_DATA_LENGTH; Index++) {
*FramePtr++ = (u8)Index;
}
/* Wait until TX FIFO has room */
while (XCan_IsTxFifoFull(InstancePtr) == TRUE);
/*
* Now send the frame.
*
* Another way to send a frame is keep calling XCan_Send() until it
* returns XST_SUCCESS. No check on if TX FIFO is full is needed anymore
* in that case.
*/
Status = XCan_Send(InstancePtr, TxFrame);
return Status;
}
/*****************************************************************************/
/**
*
* This function receives a frame and verifies its contents.
*
* @param InstancePtr is a pointer to the driver instance
*
* @return XST_SUCCESS if successful, a driver-specific return code if not.
*
* @note
*
* This function waits until RX FIFO becomes not empty before reading a frame
* from it. So this function may block if the hardware is not built
* correctly.
*
******************************************************************************/
static int RecvFrame(XCan *InstancePtr)
{
u8 *FramePtr;
int Status;
int Index;
/*
* Wait until a frame is received.
*/
while (XCan_IsRxEmpty(InstancePtr) == TRUE);
/*
* Receive a frame and verify its contents.
*/
Status = XCan_Recv(InstancePtr, RxFrame);
if (Status == XST_SUCCESS) {
/*
* Verify Identifier and Data Length Code.
*/
if (RxFrame[0] !=
XCan_CreateIdValue(TEST_MESSAGE_ID, 0, 0, 0, 0))
return XST_LOOPBACK_ERROR;
if (RxFrame[1] != XCan_CreateDlcValue(FRAME_DATA_LENGTH))
return XST_LOOPBACK_ERROR;
/*
* Verify Data field contents.
*/
FramePtr = (u8 *)(&RxFrame[2]);
for (Index = 0; Index < FRAME_DATA_LENGTH; Index++) {
if (*FramePtr++ != (u8)Index) {
return XST_LOOPBACK_ERROR;
}
}
}
return Status;
}