EK-TM4C1294XL: Issue with CAN bus transmitter code

Jayakrishnan Krishna Prasad

Part Number: EK-TM4C1294XL

I am trying to dubug the following code for CAN Tx side. I have connected the EK-TM4C1294XL board to PC using USB and using putty to view the results though the UART.

The code I am running is the following:

//*****************************************************************************

#include <stdbool.h>

#include <stdint.h>

#include "inc/hw_can.h"

#include "inc/hw_ints.h"

#include "inc/hw_memmap.h"

#include "driverlib/can.h"

#include "driverlib/gpio.h"

#include "driverlib/interrupt.h"

#include "driverlib/pin_map.h"

#include "driverlib/sysctl.h"

#include "driverlib/uart.h"

#include "utils/uartstdio.h"

#include "utils/uartstdio.c"

//*****************************************************************************

//! \addtogroup can_examples_list

//! <h1>Multiple CAN TX (multi_tx)</h1>

//!

//! This example shows how to set up the CAN to send multiple messages. The

//! CAN peripheral is configured to send messages with 4 different CAN IDs.

//! Two of the messages (with different CAN IDs) are sent using a shared

//! message object. This shows how to reuse a message object for multiple

//! messages. The other two messages are sent using their own message objects.

//! All four messages are transmitted once per second. The content of each

//! message is a test pattern. A CAN interrupt handler is used to confirm

//! message transmission and count the number of messages that have been sent.

//!

//! This example uses the following peripherals and I/O signals. You must

//! review these and change as needed for your own board:

//! - CAN1 peripheral

//! - GPIO Port B peripheral (for CAN1 pins)

//! - CAN1RX - PB0

//! - CAN1TX - PB1

//!

//! The following UART signals are configured only for displaying console

//! messages for this example. These are not required for operation of CAN.

//! - GPIO port A peripheral (for UART0 pins)

//! - UART0RX - PA0

//! - UART0TX - PA1

//!

//! This example uses the following interrupt handlers. To use this example

//! in your own application you must add these interrupt handlers to your

//! vector table.

//! - INT_CAN1 - CANIntHandler

//*****************************************************************************

// A counter that keeps track of the number of times the TX interrupt has

// occurred, which should match the number of TX messages that were sent.

//*****************************************************************************

volatile uint32_t g_ui32IntCount = 0;

//*****************************************************************************

// Counters that are used to count the number of messages on each of the

// three message objects that are used in this example.

//*****************************************************************************

volatile uint32_t g_ui32Msg1Count = 0;

volatile uint32_t g_ui32Msg2Count = 0;

volatile uint32_t g_ui32Msg3Count = 0;

//*****************************************************************************

// A flag to indicate that CAN controller message object 3 has sent a message.

//*****************************************************************************

volatile bool g_bMsgObj3Sent = 0;

//*****************************************************************************

// A flag to indicate that some transmission error occurred.

//*****************************************************************************

volatile bool g_bErrFlag = 0;

//*****************************************************************************

// CAN message objects that will hold the separate CAN messages. These could

// also be allocated on the stack but be careful because these structures

// each take about 20 bytes.

//*****************************************************************************

tCANMsgObject g_sCANMsgObject1;

tCANMsgObject g_sCANMsgObject2;

tCANMsgObject g_sCANMsgObject3;

//*****************************************************************************

// Message buffers that hold the contents of the 4 different messages that

// are being transmitted. Each one is a different length.

//*****************************************************************************

uint8_t g_pui8Msg1[4] = { 1, 3, 5, 7 };

uint8_t g_pui8Msg2[5] = { 2, 4, 6, 8, 10 };

uint8_t g_pui8Msg3[6] = { 3, 6, 9, 12, 15, 18 };

uint8_t g_pui8Msg4[8] = { 4, 8, 12, 16, 20, 24, 28, 32 };

//*****************************************************************************

// This function sets up UART0 to be used for a console to display information

// as the example is running.

//*****************************************************************************

void

InitConsole(void)

{

// Enable GPIO port A which is used for UART0 pins.

// TODO: change this to whichever GPIO port you are using.

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

// Configure the pin muxing for UART0 functions on port A0 and A1.

// This step is not necessary if your part does not support pin muxing.

// TODO: change this to select the port/pin you are using.

GPIOPinConfigure(GPIO_PA0_U0RX);

GPIOPinConfigure(GPIO_PA1_U0TX);

// Enable UART0 so that we can configure the clock.

SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

// Use the internal 16MHz oscillator as the UART clock source.

UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);

// Select the alternate (UART) function for these pins.

// TODO: change this to select the port/pin you are using.

GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

// Initialize the UART for console I/O.

UARTStdioConfig(0, 115200, 16000000);

}

//*****************************************************************************

// This function prints some information about the CAN message to the

// serial port for information purposes only.

//*****************************************************************************

void

PrintCANMessageInfo(tCANMsgObject *psCANMsg, uint32_t ui32MsgObj)

{

unsigned int uIdx;

UARTprintf("Sending msg: obj=%d ID=0x%04X msg=0x", ui32MsgObj,

psCANMsg->ui32MsgID);

for(uIdx = 0; uIdx < psCANMsg->ui32MsgLen; uIdx++)

{

UARTprintf("%02X ", psCANMsg->pui8MsgData[uIdx]);

}

UARTprintf("\n");

}

//*****************************************************************************

// This function provides a 1 second delay using a simple polling method.

//*****************************************************************************

void

SimpleDelay(void)

{

// Delay cycles for 1 second

SysCtlDelay(16000000 / 3);

}

//*****************************************************************************

// This function is the interrupt handler for the CAN peripheral. It checks

// for the cause of the interrupt, and maintains a count of all messages that

// have been transmitted.

//*****************************************************************************

void

CANIntHandler(void)

{

uint32_t ui32Status;

// Read the CAN interrupt status to find the cause of the interrupt

ui32Status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE);

// If the cause is a controller status interrupt, then get the status

if(ui32Status == CAN_INT_INTID_STATUS)

{

// Read the controller status. This will return a field of status

// error bits that can indicate various errors. Error processing

// is not done in this example for simplicity. Refer to the

// API documentation for details about the error status bits.

// The act of reading this status will clear the interrupt. If the

// CAN peripheral is not connected to a CAN bus with other CAN devices

// present, then errors will occur and will be indicated in the

// controller status.

ui32Status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL);

// Set a flag to indicate some errors may have occurred.

g_bErrFlag = 1;

}

// Check if the cause is message object 1, which is used for sending

// message 1.

else if(ui32Status == 1)

{

// Getting to this point means that the TX interrupt occurred on

// message object 1, and the message TX is complete. Clear the

// message object interrupt.

CANIntClear(CAN1_BASE, 1);

// Increment a counter to keep track of how many messages have been

// sent. In a real application this could be used to set flags to

// indicate when a message is sent.

g_ui32Msg1Count++;

// Since the message was sent, clear any error flags.

g_bErrFlag = 0;

}

// Check if the cause is message object 2, which is used for sending

// message 2.

else if(ui32Status == 2)

{

// Getting to this point means that the TX interrupt occurred on

// message object 2, and the message TX is complete. Clear the

// message object interrupt.

CANIntClear(CAN1_BASE, 2);

// Increment a counter to keep track of how many messages have been

// sent. In a real application this could be used to set flags to

// indicate when a message is sent.

g_ui32Msg2Count++;

// Since the message was sent, clear any error flags.

g_bErrFlag = 0;

}

// Check if the cause is message object 3, which is used for sending

// messages 3 and 4.

else if(ui32Status == 3)

{

// Getting to this point means that the TX interrupt occurred on

// message object 3, and a message TX is complete. Clear the

// message object interrupt.

CANIntClear(CAN1_BASE, 3);

// Increment a counter to keep track of how many messages have been

// sent. In a real application this could be used to set flags to

// indicate when a message is sent.

g_ui32Msg3Count++;

// Set the flag indicating that a message was sent using message

// object 3. The program main loop uses this to know when to send

// another message using message object 3.

g_bMsgObj3Sent = 1;

// Since the message was sent, clear any error flags.

g_bErrFlag = 0;

}

// Otherwise, something unexpected caused the interrupt. This should

// never happen.

else

{

// Spurious interrupt handling can go here.

}

//*****************************************************************************

// Configure the CAN and enter a loop to transmit periodic CAN messages.

//*****************************************************************************

int

main(void)

{

uint32_t ui32SysClock;

ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_16MHZ |

SYSCTL_OSC_INT |

SYSCTL_USE_PLL |

SYSCTL_CFG_VCO_480), 120000000);

// 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 CAN1 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 CAN1 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_PB0_CAN1RX);

GPIOPinConfigure(GPIO_PB1_CAN1TX);

// 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_0 | GPIO_PIN_1);

// The GPIO port and pins have been set up for CAN. The CAN peripheral

// must be enabled.

SysCtlPeripheralDisable(SYSCTL_PERIPH_CAN1);

SysCtlPeripheralReset(SYSCTL_PERIPH_CAN1);

SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);

// Initialize the CAN controller

CANInit(CAN1_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(CAN1_BASE, ui32SysClock, 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(CAN1_BASE, CANIntHandler); // if using dynamic vectors

CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);

// Enable the CAN interrupt on the processor (NVIC).

IntEnable(INT_CAN1);

// Enable the CAN for operation.

CANEnable(CAN1_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(CAN1_BASE, 1, &g_sCANMsgObject1, MSG_OBJ_TYPE_TX);

UARTprintf("%d\n",g_ui32Msg1Count);

// 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(CAN1_BASE, 2, &g_sCANMsgObject2, MSG_OBJ_TYPE_TX);

UARTprintf("%d\n",g_ui32Msg2Count);

// 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(CAN1_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)

{

}

UARTprintf("%d\n",g_ui32Msg3Count);

// 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(CAN1_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);

}

// Return no errors

//return(0);

}

The result of the above code is:

Please note the lines in red coloured font in the code.

The above in putty is received when the UARTprintf("%d\n",g_ui32Msg3Count); is included after while(!g_bMsgObj3Sent) { }

But if I include the UARTprintf("%d\n",g_ui32Msg3Count) before while(!g_bMsgObj3Sent) { } I am getting the below shown result in putty:

So the program execution seems to be stuck in the while loop: while(!g_bMsgObj3Sent) { }

The program is designed to reuse the message object to send multiple data.

Is there any remedy ?

//*****************************************************************************//// multi_tx.c - Peripheral example demonstrating multiple CAN message// transmission.//// Copyright (c) 2010-2014 Texas Instruments Incorporated. All rights reserved.// Software License Agreement//// Redistribution and use in source and binary forms, with or without// modification, are permitted provided that the following conditions// are met://// Redistributions of source code must retain the above copyright// notice, this list of conditions and the following disclaimer.//// Redistributions in binary form must reproduce the above copyright// notice, this list of conditions and the following disclaimer in the// documentation and/or other materials provided with the// distribution.//// Neither the name of Texas Instruments Incorporated nor the names of// its contributors may be used to endorse or promote products derived// from this software without specific prior written permission.//// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.//// This is part of revision 2.1.0.12573 of the Tiva Firmware Development Package.////*****************************************************************************
#include <stdbool.h>#include <stdint.h>#include "inc/hw_can.h"#include "inc/hw_ints.h"#include "inc/hw_memmap.h"#include "driverlib/can.h"#include "driverlib/gpio.h"#include "driverlib/interrupt.h"#include "driverlib/pin_map.h"#include "driverlib/sysctl.h"#include "driverlib/uart.h"#include "utils/uartstdio.h"#include "utils/uartstdio.c"
//*****************************************************************************////! \addtogroup can_examples_list//! <h1>Multiple CAN TX (multi_tx)</h1>//!//! This example shows how to set up the CAN to send multiple messages. The//! CAN peripheral is configured to send messages with 4 different CAN IDs.//! Two of the messages (with different CAN IDs) are sent using a shared//! message object. This shows how to reuse a message object for multiple//! messages. The other two messages are sent using their own message objects.//! All four messages are transmitted once per second. The content of each//! message is a test pattern. A CAN interrupt handler is used to confirm//! message transmission and count the number of messages that have been sent.//!//! This example uses the following peripherals and I/O signals. You must//! review these and change as needed for your own board://! - CAN1 peripheral//! - GPIO Port B peripheral (for CAN1 pins)//! - CAN1RX - PB0//! - CAN1TX - PB1//!//! The following UART signals are configured only for displaying console//! messages for this example. These are not required for operation of CAN.//! - GPIO port A peripheral (for UART0 pins)//! - UART0RX - PA0//! - UART0TX - PA1//!//! This example uses the following interrupt handlers. To use this example//! in your own application you must add these interrupt handlers to your//! vector table.//! - INT_CAN1 - CANIntHandler////*****************************************************************************
//*****************************************************************************//// A counter that keeps track of the number of times the TX interrupt has// occurred, which should match the number of TX messages that were sent.////*****************************************************************************volatile uint32_t g_ui32IntCount = 0;
//*****************************************************************************//// Counters that are used to count the number of messages on each of the// three message objects that are used in this example.////*****************************************************************************volatile uint32_t g_ui32Msg1Count = 0;volatile uint32_t g_ui32Msg2Count = 0;volatile uint32_t g_ui32Msg3Count = 0;
//*****************************************************************************//// A flag to indicate that CAN controller message object 3 has sent a message.////*****************************************************************************volatile bool g_bMsgObj3Sent = 0;
//*****************************************************************************//// A flag to indicate that some transmission error occurred.////*****************************************************************************volatile bool g_bErrFlag = 0;
//*****************************************************************************//// CAN message objects that will hold the separate CAN messages. These could// also be allocated on the stack but be careful because these structures// each take about 20 bytes.////*****************************************************************************tCANMsgObject g_sCANMsgObject1;tCANMsgObject g_sCANMsgObject2;tCANMsgObject g_sCANMsgObject3;
//*****************************************************************************//// Message buffers that hold the contents of the 4 different messages that// are being transmitted. Each one is a different length.////*****************************************************************************uint8_t g_pui8Msg1[4] = { 1, 3, 5, 7 };uint8_t g_pui8Msg2[5] = { 2, 4, 6, 8, 10 };uint8_t g_pui8Msg3[6] = { 3, 6, 9, 12, 15, 18 };uint8_t g_pui8Msg4[8] = { 4, 8, 12, 16, 20, 24, 28, 32 };
//*****************************************************************************//// This function sets up UART0 to be used for a console to display information// as the example is running.////*****************************************************************************voidInitConsole(void){ // // Enable GPIO port A which is used for UART0 pins. // TODO: change this to whichever GPIO port you are using. // SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
// // Configure the pin muxing for UART0 functions on port A0 and A1. // This step is not necessary if your part does not support pin muxing. // TODO: change this to select the port/pin you are using. // GPIOPinConfigure(GPIO_PA0_U0RX); GPIOPinConfigure(GPIO_PA1_U0TX);
// // Enable UART0 so that we can configure the clock. // SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
// // Use the internal 16MHz oscillator as the UART clock source. // UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
// // Select the alternate (UART) function for these pins. // TODO: change this to select the port/pin you are using. // GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
// // Initialize the UART for console I/O. // UARTStdioConfig(0, 115200, 16000000);}
//*****************************************************************************//// This function prints some information about the CAN message to the// serial port for information purposes only.////*****************************************************************************voidPrintCANMessageInfo(tCANMsgObject *psCANMsg, uint32_t ui32MsgObj){ unsigned int uIdx;
UARTprintf("Sending msg: obj=%d ID=0x%04X msg=0x", ui32MsgObj, psCANMsg->ui32MsgID); for(uIdx = 0; uIdx < psCANMsg->ui32MsgLen; uIdx++) { UARTprintf("%02X ", psCANMsg->pui8MsgData[uIdx]); } UARTprintf("\n");}
//*****************************************************************************//// This function provides a 1 second delay using a simple polling method.////*****************************************************************************voidSimpleDelay(void){ // // Delay cycles for 1 second // SysCtlDelay(16000000 / 3);}
//*****************************************************************************//// This function is the interrupt handler for the CAN peripheral. It checks// for the cause of the interrupt, and maintains a count of all messages that// have been transmitted.////*****************************************************************************voidCANIntHandler(void){ uint32_t ui32Status;
// // Read the CAN interrupt status to find the cause of the interrupt // ui32Status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE);
// // If the cause is a controller status interrupt, then get the status // if(ui32Status == CAN_INT_INTID_STATUS) { // // Read the controller status. This will return a field of status // error bits that can indicate various errors. Error processing // is not done in this example for simplicity. Refer to the // API documentation for details about the error status bits. // The act of reading this status will clear the interrupt. If the // CAN peripheral is not connected to a CAN bus with other CAN devices // present, then errors will occur and will be indicated in the // controller status. // ui32Status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL);
// // Set a flag to indicate some errors may have occurred. // g_bErrFlag = 1; }
// // Check if the cause is message object 1, which is used for sending // message 1. // else if(ui32Status == 1) { // // Getting to this point means that the TX interrupt occurred on // message object 1, and the message TX is complete. Clear the // message object interrupt. // CANIntClear(CAN1_BASE, 1);
// // Increment a counter to keep track of how many messages have been // sent. In a real application this could be used to set flags to // indicate when a message is sent. // g_ui32Msg1Count++;
// // Since the message was sent, clear any error flags. // g_bErrFlag = 0; }
// // Check if the cause is message object 2, which is used for sending // message 2. // else if(ui32Status == 2) { // // Getting to this point means that the TX interrupt occurred on // message object 2, and the message TX is complete. Clear the // message object interrupt. // CANIntClear(CAN1_BASE, 2);
// // Increment a counter to keep track of how many messages have been // sent. In a real application this could be used to set flags to // indicate when a message is sent. // g_ui32Msg2Count++;
// // Since the message was sent, clear any error flags. // g_bErrFlag = 0; }
// // Check if the cause is message object 3, which is used for sending // messages 3 and 4. // else if(ui32Status == 3) { // // Getting to this point means that the TX interrupt occurred on // message object 3, and a message TX is complete. Clear the // message object interrupt. // CANIntClear(CAN1_BASE, 3);
// // Increment a counter to keep track of how many messages have been // sent. In a real application this could be used to set flags to // indicate when a message is sent. // g_ui32Msg3Count++;
// // Set the flag indicating that a message was sent using message // object 3. The program main loop uses this to know when to send // another message using message object 3. // g_bMsgObj3Sent = 1;
// // Since the message was sent, clear any error flags. // g_bErrFlag = 0; }
// // Otherwise, something unexpected caused the interrupt. This should // never happen. // else { // // Spurious interrupt handling can go here. // }}
//*****************************************************************************//// Configure the CAN and enter a loop to transmit periodic CAN messages.////*****************************************************************************intmain(void){ uint32_t ui32SysClock;
ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_16MHZ | SYSCTL_OSC_INT | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000); // // 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 CAN1 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 CAN1 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_PB0_CAN1RX); GPIOPinConfigure(GPIO_PB1_CAN1TX);
// // 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_0 | GPIO_PIN_1);
// // The GPIO port and pins have been set up for CAN. The CAN peripheral // must be enabled. // SysCtlPeripheralDisable(SYSCTL_PERIPH_CAN1); SysCtlPeripheralReset(SYSCTL_PERIPH_CAN1); SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);
// // Initialize the CAN controller // CANInit(CAN1_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(CAN1_BASE, ui32SysClock, 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(CAN1_BASE, CANIntHandler); // if using dynamic vectors // CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
// // Enable the CAN interrupt on the processor (NVIC). // IntEnable(INT_CAN1);
// // Enable the CAN for operation. // CANEnable(CAN1_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(CAN1_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(CAN1_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(CAN1_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(CAN1_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);

}

// // Return no errors // //return(0);}

over 8 years ago

0 Bruno Saraiva over 8 years ago

Guru 13040 points

Dear Sir,

Please edit your original post to make it more clear and avoid the risk of being ignored. It is almost impossible to even find a question in it.

- Cut the code, past it using the </> button of the formatting bar.

- Erase the hundreds of continuous code lines after the graphics

- Maybe consider posting only the relevant part of the code

Thank you

Bruno

0 Jayakrishnan Krishna Prasad over 8 years ago in reply to Bruno Saraiva

Prodigy 180 points

I am trying to dubug the following code for CAN Tx side. I have connected the EK-TM4C1294XL board to PC using USB and using putty to view the results though the UART.

The code I am running is the following:

#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_can.h"
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "driverlib/can.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"
#include "utils/uartstdio.c"

volatile uint32_t g_ui32IntCount = 0;
volatile uint32_t g_ui32Msg1Count = 0;
volatile uint32_t g_ui32Msg2Count = 0;
volatile uint32_t g_ui32Msg3Count = 0;

volatile bool g_bMsgObj3Sent = 0;
volatile bool g_bErrFlag = 0;


tCANMsgObject g_sCANMsgObject1;
tCANMsgObject g_sCANMsgObject2;
tCANMsgObject g_sCANMsgObject3;

uint8_t g_pui8Msg1[4] = { 1, 3, 5, 7 };
uint8_t g_pui8Msg2[5] = { 2, 4, 6, 8, 10 };
uint8_t g_pui8Msg3[6] = { 3, 6, 9, 12, 15, 18 };
uint8_t g_pui8Msg4[8] = { 4, 8, 12, 16, 20, 24, 28, 32 };

void InitConsole(void)
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    UARTStdioConfig(0, 115200, 16000000);
}


void PrintCANMessageInfo(tCANMsgObject *psCANMsg, uint32_t ui32MsgObj)
{
    unsigned int uIdx;
    UARTprintf("Sending msg: obj=%d ID=0x%04X msg=0x", ui32MsgObj,psCANMsg->ui32MsgID);
             
    for(uIdx = 0; uIdx < psCANMsg->ui32MsgLen; uIdx++)
    {
    	UARTprintf("%02X ", psCANMsg->pui8MsgData[uIdx]);
    }
    UARTprintf("\n");
}


void SimpleDelay(void)
{
    SysCtlDelay(16000000 / 3);

}

void CANIntHandler(void)
{

    uint32_t ui32Status;
  
    ui32Status = CANIntStatus(CAN1_BASE, CAN_INT_STS_CAUSE);

    if(ui32Status == CAN_INT_INTID_STATUS)
    {

    	ui32Status = CANStatusGet(CAN1_BASE, CAN_STS_CONTROL);
        g_bErrFlag = 1;
    }

    else if(ui32Status == 1)
    {
    	CANIntClear(CAN1_BASE, 1);
        g_ui32Msg1Count++;
        g_bErrFlag = 0;
    }

    else if(ui32Status == 2)
    {
	CANIntClear(CAN1_BASE, 2);
        g_ui32Msg2Count++;
        g_bErrFlag = 0;
    }

    else if(ui32Status == 3)
    {

        CANIntClear(CAN1_BASE, 3);
        g_ui32Msg3Count++;
        g_bMsgObj3Sent = 1;
        g_bErrFlag = 0;
    }

}


int main(void)
{

    uint32_t ui32SysClock;
    ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_16MHZ | SYSCTL_OSC_INT | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);
   
    InitConsole();

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
    GPIOPinConfigure(GPIO_PB0_CAN1RX);
    GPIOPinConfigure(GPIO_PB1_CAN1TX);
    GPIOPinTypeCAN(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    SysCtlPeripheralDisable(SYSCTL_PERIPH_CAN1);
    SysCtlPeripheralReset(SYSCTL_PERIPH_CAN1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_CAN1);
    CANInit(CAN1_BASE);
    CANBitRateSet(CAN1_BASE, ui32SysClock, 500000);
    CANIntRegister(CAN1_BASE, CANIntHandler); 
    CANIntEnable(CAN1_BASE, CAN_INT_MASTER | CAN_INT_ERROR | CAN_INT_STATUS);
    IntEnable(INT_CAN1);
    CANEnable(CAN1_BASE);

    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;

    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;

    for(;;)
    {
        PrintCANMessageInfo(&g_sCANMsgObject1, 1);
        CANMessageSet(CAN1_BASE, 1, &g_sCANMsgObject1, MSG_OBJ_TYPE_TX);
        UARTprintf("%d\n",g_ui32Msg1Count);

        PrintCANMessageInfo(&g_sCANMsgObject2, 2);
        CANMessageSet(CAN1_BASE, 2, &g_sCANMsgObject2, MSG_OBJ_TYPE_TX);
        UARTprintf("%d\n",g_ui32Msg2Count);

        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;
       
        g_bMsgObj3Sent = 0;

        PrintCANMessageInfo(&g_sCANMsgObject3, 3);
        CANMessageSet(CAN1_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);

        while(!g_bMsgObj3Sent) 
	{
	}

        UARTprintf("%d\n",g_ui32Msg3Count); 

        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;

        PrintCANMessageInfo(&g_sCANMsgObject3, 3);

        CANMessageSet(CAN1_BASE, 3, &g_sCANMsgObject3, MSG_OBJ_TYPE_TX);
    }

}

The above in Putty is received when the UARTprintf("%d\n",g_ui32Msg3Count); is included after while(!g_bMsgObj3Sent) { } .

But if I include the UARTprintf("%d\n",g_ui32Msg3Count) before while(!g_bMsgObj3Sent) { } I am getting the below shown result in Putty:

So the program execution seems to be stuck in the while loop: while(!g_bMsgObj3Sent) { }

The for loop is not getting executed infinitely. What is the remedy ?

0 cb1_mobile over 8 years ago in reply to Jayakrishnan Krishna Prasad

Guru 117855 points

Both of your screen caps provide (ONLY) ~10% usable data (of very poor contrast!) - rest is useless. (which obscures your key findings - that's NOT good!) You may remedy that by performing a "2nd operation" upon the screen cap - (editing it to just the essentials - that vast dead/"black" space provides NO value!) And choose more contrasting/brighter (i.e. readable) screen colors.

Recall that (many) posters arrive here "seeking help" - you must make (some) effort to "Sell your post" so that it receives adequate attention... (legibility really counts!)

Jayakrishnan Krishna Prasad said:

So the program execution seems to be stuck in the while loop: while(!g_bMsgObj3Sent) { }

The for loop is not getting executed infinitely. What is the remedy ?

As to your code review - I find that "while loop" - yet no (included) "for loop" - which you suggest is present and NOT (fully) executed!

Arm-based microcontrollers

Arm-based microcontrollers forum

EK-TM4C1294XL: Issue with CAN bus transmitter code