//*****************************************************************************
//
// Configure the CAN and enter a loop to receive CAN messages.
//
//*****************************************************************************
int
main(void)
{
tCANMsgObject sCANMessage;
uint8_t pui8MsgData[8];
//
// Set the clocking to run directly from the external crystal/oscillator.
// TODO: The SYSCTL_XTAL_ value must be changed to match the value of the
// crystal used on your board.
//
SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);
//
// Set up the serial console to use for displaying messages. This is
// just for this example program and is not needed for CAN operation.
//
InitConsole();
//
// For this example CAN0 is used with RX and TX pins on port B4 and B5.
// The actual port and pins used may be different on your part, consult
// the data sheet for more information.
// GPIO port B needs to be enabled so these pins can be used.
// TODO: change this to whichever GPIO port you are using
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
//
// Configure the GPIO pin muxing to select CAN0 functions for these pins.
// This step selects which alternate function is available for these pins.
// This is necessary if your part supports GPIO pin function muxing.
// Consult the data sheet to see which functions are allocated per pin.
// TODO: change this to select the port/pin you are using
//
GPIOPinConfigure(GPIO_PB4_CAN0RX);
GPIOPinConfigure(GPIO_PB5_CAN0TX);
//
// Enable the alternate function on the GPIO pins. The above step selects
// which alternate function is available. This step actually enables the
// alternate function instead of GPIO for these pins.
// TODO: change this to match the port/pin you are using
//
GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_4 | GPIO_PIN_5);
//
// The GPIO port and pins have been set up for CAN. The CAN peripheral
// must be enabled.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN0);
//
// Initialize the CAN controller
//
CANInit(CAN0_BASE);
//
// Set up the bit rate for the CAN bus. This function sets up the CAN
// bus timing for a nominal configuration. You can achieve more control
// over the CAN bus timing by using the function CANBitTimingSet() instead
// of this one, if needed.
// In this example, the CAN bus is set to 500 kHz. In the function below,
// the call to SysCtlClockGet() is used to determine the clock rate that
// is used for clocking the CAN peripheral. This can be replaced with a
// fixed value if you know the value of the system clock, saving the extra
// function call. For some parts, the CAN peripheral is clocked by a fixed
// 8 MHz regardless of the system clock in which case the call to
// SysCtlClockGet() should be replaced with 8000000. Consult the data
// sheet for more information about CAN peripheral clocking.
//
CANBitRateSet(CAN0_BASE, SysCtlClockGet(), 500000);
//
// Enable interrupts on the CAN peripheral. This example uses static
// allocation of interrupt handlers which means the name of the handler
// is in the vector table of startup code. If you want to use dynamic
// allocation of the vector table, then you must also call CANIntRegister()
// here.
//
// CANIntRegister(CAN0_BASE, CAN0_IRQHandler); // if using dynamic vectors
//
CANIntEnable(CAN0_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
//
// Enable the CAN interrupt on the processor (NVIC).
//
IntEnable(INT_CAN0);
//
// Enable the CAN for operation.
//
CANEnable(CAN0_BASE);
//
// Initialize a message object to receive CAN messages with ID 0x1001.
// The expected ID must be set along with the mask to indicate that all
// bits in the ID must match.
//
sCANMessage.ui32MsgID = 0x1001;
sCANMessage.ui32MsgIDMask = 0xfffff;
sCANMessage.ui32Flags = (MSG_OBJ_RX_INT_ENABLE | MSG_OBJ_USE_ID_FILTER |
MSG_OBJ_EXTENDED_ID);
sCANMessage.ui32MsgLen = 8;
//
// Now load the message object into the CAN peripheral message object 1.
// Once loaded the CAN will receive any messages with this CAN ID into
// this message object, and an interrupt will occur.
//
CANMessageSet(CAN0_BASE, 1, &sCANMessage, MSG_OBJ_TYPE_RX);
//
// Change the ID to 0x2001, and load into message object 2 which will be
// used for receiving any CAN messages with this ID. Since only the CAN
// ID field changes, we don't need to reload all the other fields.
//
sCANMessage.ui32MsgID = 0x2001;
CANMessageSet(CAN0_BASE, 2, &sCANMessage, MSG_OBJ_TYPE_RX);
//
// Change the ID to 0x3001, and load into message object 3 which will be
// used for receiving any CAN messages with this ID. Since only the CAN
// ID field changes, we don't need to reload all the other fields.
//
sCANMessage.ui32MsgID = 0x3001;
CANMessageSet(CAN0_BASE, 3, &sCANMessage, MSG_OBJ_TYPE_RX);
//
// Enter loop to process received messages. This loop just checks flags
// for each of the 3 expected messages. The flags are set by the interrupt
// handler, and if set this loop reads out the message and displays the
// contents to the console. This is not a robust method for processing
// incoming CAN data and can only handle one messages at a time per message
// object. If many messages are being received close together using the
// same message object, then some messages may be dropped. In a real
// application, some other method should be used for queuing received
// messages in a way to ensure they are not lost. You can also make use
// of CAN FIFO mode which will allow messages to be buffered before they
// are processed.
//
for(;;)
{
//
// If the flag for message object 1 is set, that means that the RX
// interrupt occurred and there is a message ready to be read from
// this CAN message object.
//
if(g_bRXFlag1)
{
//
// Reuse the same message object that was used earlier to configure
// the CAN for receiving messages. A buffer for storing the
// received data must also be provided, so set the buffer pointer
// within the message object. This same buffer is used for all
// messages in this example, but your application could set a
// different buffer each time a message is read in order to store
// different messages in different buffers.
//
sCANMessage.pui8MsgData = pui8MsgData;
//
// Read the message from the CAN. Message object number 1 is used
// (which is not the same thing as CAN ID). The interrupt clearing
// flag is not set because this interrupt was already cleared in
// the interrupt handler.
//
CANMessageGet(CAN0_BASE, 1, &sCANMessage, 0);
//
// Clear the pending message flag so that the interrupt handler can
// set it again when the next message arrives.
//
g_bRXFlag1 = 0;
//
// Print information about the message just received.
//
PrintCANMessageInfo(&sCANMessage, 1);
}
//
// Check for message received on message object 2. If so then
// read message and print information.
//
if(g_bRXFlag2)
{
sCANMessage.pui8MsgData = pui8MsgData;
CANMessageGet(CAN0_BASE, 2, &sCANMessage, 0);
g_bRXFlag2 = 0;
PrintCANMessageInfo(&sCANMessage, 2);
}
//
// Check for message received on message object 3. If so then
// read message and print information.
//
if(g_bRXFlag3)
{
sCANMessage.pui8MsgData = pui8MsgData;
CANMessageGet(CAN0_BASE, 3, &sCANMessage, 0);
g_bRXFlag3 = 0;
PrintCANMessageInfo(&sCANMessage, 3);
}
}
//
// Return no errors
//
return(0);
}
//*****************************************************************************
//
// Configure the CAN and enter a loop to transmit periodic CAN messages.
//
//*****************************************************************************
int
main(void)
{
//
// Set the clocking to run directly from the external crystal/oscillator.
// TODO: The SYSCTL_XTAL_ value must be changed to match the value of the
// crystal on your board.
//
SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);
//
// Set up the serial console to use for displaying messages. This is
// just for this example program and is not needed for CAN operation.
//
InitConsole();
//
// For this example CAN0 is used with RX and TX pins on port B4 and B5.
// The actual port and pins used may be different on your part, consult
// the data sheet for more information.
// GPIO port B needs to be enabled so these pins can be used.
// TODO: change this to whichever GPIO port you are using
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
//
// Configure the GPIO pin muxing to select CAN0 functions for these pins.
// This step selects which alternate function is available for these pins.
// This is necessary if your part supports GPIO pin function muxing.
// Consult the data sheet to see which functions are allocated per pin.
// TODO: change this to select the port/pin you are using
//
GPIOPinConfigure(GPIO_PB4_CAN0RX);
GPIOPinConfigure(GPIO_PB5_CAN0TX);
//
// Enable the alternate function on the GPIO pins. The above step selects
// which alternate function is available. This step actually enables the
// alternate function instead of GPIO for these pins.
// TODO: change this to match the port/pin you are using
//
GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_4 | GPIO_PIN_5);
//
// The GPIO port and pins have been set up for CAN. The CAN peripheral
// must be enabled.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN0);
//
// Initialize the CAN controller
//
CANInit(CAN0_BASE);
//
// Set up the bit rate for the CAN bus. This function sets up the CAN
// bus timing for a nominal configuration. You can achieve more control
// over the CAN bus timing by using the function CANBitTimingSet() instead
// of this one, if needed.
// In this example, the CAN bus is set to 500 kHz. In the function below,
// the call to SysCtlClockGet() is used to determine the clock rate that
// is used for clocking the CAN peripheral. This can be replaced with a
// fixed value if you know the value of the system clock, saving the extra
// function call. For some parts, the CAN peripheral is clocked by a fixed
// 8 MHz regardless of the system clock in which case the call to
// SysCtlClockGet() should be replaced with 8000000. Consult the data
// sheet for more information about CAN peripheral clocking.
//
CANBitRateSet(CAN0_BASE, SysCtlClockGet(), 500000);
//
// Enable interrupts on the CAN peripheral. This example uses static
// allocation of interrupt handlers which means the name of the handler
// is in the vector table of startup code. If you want to use dynamic
// allocation of the vector table, then you must also call CANIntRegister()
// here.
//
// CANIntRegister(CAN0_BASE, CANIntHandler); // if using dynamic vectors
//
CANIntEnable(CAN0_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
//
// Enable the CAN interrupt on the processor (NVIC).
//
IntEnable(INT_CAN0);
//
// Enable the CAN for operation.
//
CANEnable(CAN0_BASE);
//
// Initialize the message object that will be used for sending CAN
// messages. The message will be 4 bytes that will contain an incrementing
// value. Initially it will be set to 0.
//
//
// Initialize message object 1 to be able to send CAN message 1. This
// message object is not shared so it only needs to be initialized one
// time, and can be used for repeatedly sending the same message ID.
//
g_sCANMsgObject1.ui32MsgID = 0x1001;
g_sCANMsgObject1.ui32MsgIDMask = 0;
g_sCANMsgObject1.ui32Flags = MSG_OBJ_TX_INT_ENABLE;
g_sCANMsgObject1.ui32MsgLen = sizeof(g_pui8Msg1);
g_sCANMsgObject1.pui8MsgData = g_pui8Msg1;
//
// Initialize message object 2 to be able to send CAN message 2. This
// message object is not shared so it only needs to be initialized one
// time, and can be used for repeatedly sending the same message ID.
//
g_sCANMsgObject2.ui32MsgID = 0x2001;
g_sCANMsgObject2.ui32MsgIDMask = 0;
g_sCANMsgObject2.ui32Flags = MSG_OBJ_TX_INT_ENABLE;
g_sCANMsgObject2.ui32MsgLen = sizeof(g_pui8Msg2);
g_sCANMsgObject2.pui8MsgData = g_pui8Msg2;
//
// Enter loop to send messages. Four messages will be sent once per
// second. The contents of each message will be changed each time.
//
for(;;)
{
//
// Send message 1 using CAN controller message object 1. This is
// the only message sent using this message object. The
// CANMessageSet() function will cause the message to be sent right
// away.
//
PrintCANMessageInfo(&g_sCANMsgObject1, 1);
CANMessageSet(CAN0_BASE, 1, &g_sCANMsgObject1, MSG_OBJ_TYPE_TX);
//
// Send message 2 using CAN controller message object 2. This is
// the only message sent using this message object. The
// CANMessageSet() function will cause the message to be sent right
// away.
//
PrintCANMessageInfo(&g_sCANMsgObject2, 2);
CANMessageSet(CAN0_BASE, 2, &g_sCANMsgObject2, MSG_OBJ_TYPE_TX);
//
// Load message object 3 with message 3. This is needs to be done each
// time because message object 3 is being shared for two different
// messages.
//
g_sCANMsgObject3.ui32MsgID = 0x3001;
g_sCANMsgObject3.ui32MsgIDMask = 0;
g_sCANMsgObject3.ui32Flags = MSG_OBJ_TX_INT_ENABLE;
g_sCANMsgObject3.ui32MsgLen = sizeof(g_pui8Msg3);
g_sCANMsgObject3.pui8MsgData = g_pui8Msg3;
//
// Clear the flag that indicates that message 3 has been sent. This
// flag will be set in the interrupt handler when a message has been
// sent using message object 3.
//
g_bMsgObj3Sent = 0;
//
// Now send message 3 using CAN controller message object 3. This is
// the first message sent using this message object. The
// CANMessageSet() function will cause the message to be sent right
// away.
//
PrintCANMessageInfo(&g_sCANMsgObject3, 3);
CANMessageSet(CAN0_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);
//
// Wait for the indication from the interrupt handler that message
// object 3 is done, because we are re-using it for another message.
//
while(!g_bMsgObj3Sent)
{
}
//
// Load message object 3 with message 4. This is needed because
// message object 3 is being shared for two different messages.
//
g_sCANMsgObject3.ui32MsgID = 0x3002;
g_sCANMsgObject3.ui32MsgIDMask = 0;
g_sCANMsgObject3.ui32Flags = MSG_OBJ_TX_INT_ENABLE;
g_sCANMsgObject3.ui32MsgLen = sizeof(g_pui8Msg4);
g_sCANMsgObject3.pui8MsgData = g_pui8Msg4;
//
// Now send message 4 using CAN controller message object 3. This is
// the second message sent using this message object. The
// CANMessageSet() function will cause the message to be sent right
// away.
//
PrintCANMessageInfo(&g_sCANMsgObject3, 3);
CANMessageSet(CAN0_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);
//
// Wait 1 second before continuing
//
SimpleDelay();
//
// Check the error flag to see if errors occurred
//
if(g_bErrFlag)
{
UARTprintf(" error - cable connected?\n");
}
else
{
//
// If no errors then print the count of message sent
//
UARTprintf(" total count = %u\n",
g_ui32Msg1Count + g_ui32Msg2Count + g_ui32Msg3Count);
}
//
// Change the value in the message data for each of the messages.
//
(*(uint32_t *)g_pui8Msg1)++;
(*(uint32_t *)g_pui8Msg2)++;
(*(uint32_t *)g_pui8Msg3)++;
(*(uint32_t *)&g_pui8Msg4[0])++;
(*(uint32_t *)&g_pui8Msg4[4])--;
}
//
// Return no errors
//
return(0);
}
