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TM4C123GH6PM: Problem with the CAN reception

Part Number: TM4C123GH6PM


Hello everyone,

I wanted to build a CAN communication between 2 Tiva-C boards (tm4c123gh6pm), but there was something wrong with the reception.

Tool: IAR 8.11

Code(originating from the TI example "simple_rx.c"):

main.c:

#define PART_TM4C123GH6PM

//*****************************************************************************
//
// simple_rx.c - Example demonstrating simple CAN message reception.
//
// Copyright (c) 2010-2017 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 2.1.4.178 of the Tiva Firmware Development Package.
//
//*****************************************************************************

#include <stdbool.h>
#include <stdint.h>

#include <stdio.h>

#include "inc/hw_can.h"
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"

#include "driverlib/debug.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"

//*****************************************************************************
//
//! \addtogroup can_examples_list
//! <h1>Simple CAN RX (simple_rx)</h1>
//!
//! This example shows the basic setup of CAN in order to receive messages
//! from the CAN bus.  The CAN peripheral is configured to receive messages
//! with any CAN ID and then print the message contents to the console.
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - CAN0 peripheral
//! - GPIO port B peripheral (for CAN0 pins)
//! - CAN0RX - PB4
//! - CAN0TX - PB5
//!
//! 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_CAN0 - CANIntHandler
//
//*****************************************************************************

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
    while(1);
}
#endif

//*****************************************************************************
//
// A counter that keeps track of the number of times the RX interrupt has
// occurred, which should match the number of messages that were received.
//
//*****************************************************************************
volatile uint32_t g_ui32MsgCount = 0;

//*****************************************************************************
//
// A flag for the interrupt handler to indicate that a message was received.
//
//*****************************************************************************
volatile bool g_bRXFlag = 0;

//*****************************************************************************
//
// A flag to indicate that some reception error occurred.
//
//*****************************************************************************
volatile bool g_bErrFlag = 0;

//*****************************************************************************
//
// This function sets up GPIOF to be used for the LED to display status of can 
// message transmission.
//
//*****************************************************************************
void
InitLED(void)
{
    //
    // Enable the GPIO port that is used for the on-board LED.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Check if the peripheral access is enabled.
    //
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOF))
    {
    }

    //
    // Enable the GPIO pin for the LED (PF1,PF2 and PF3).  Set the direction as output, and
    // enable the GPIO pin for digital function.
    //
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3);
}

//*****************************************************************************
//
// 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 provides a 1 second delay using a simple polling method.
//
//*****************************************************************************
void
SimpleDelay(int div)
{
    //
    // Delay cycles for 1/div second
    //
    SysCtlDelay(16000000 / 3 / div);
}

//*****************************************************************************
//
// 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 received.
//
//*****************************************************************************
void
CANIntHandler(void)
{
    uint32_t ui32Status;

    //
    // Read the CAN interrupt status to find the cause of the interrupt
    //
    ui32Status = CANIntStatus(CAN0_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.
        //
        ui32Status = CANStatusGet(CAN0_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 what we are using for
    // receiving messages.
    //
    else if(ui32Status == 1)
    {
        //
        // Getting to this point means that the RX interrupt occurred on
        // message object 1, and the message reception is complete.  Clear the
        // message object interrupt.
        //
        CANIntClear(CAN0_BASE, 1);

        //
        // Increment a counter to keep track of how many messages have been
        // received.  In a real application this could be used to set flags to
        // indicate when a message is received.
        //
        g_ui32MsgCount++;

        //
        // Set flag to indicate received message is pending.
        //
        g_bRXFlag = 1;

        //
        // Since a message was received, 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 receive CAN messages.
//
//*****************************************************************************
int
main(void)
{
/*
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    uint32_t ui32SysClock;
#endif
*/
    uint32_t ui32SysClock;

    tCANMsgObject sCANMessage;
    //uint8_t pui8MsgData[8];
    uint8_t pui8MsgData[4];

    //
    // 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.
    //
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                       SYSCTL_OSC_MAIN |
                                       SYSCTL_USE_OSC)
                                       25000000);
#else
    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_16MHZ);
#endif

    //
    // Set up the LED to use for displaying CAN transmission status.  This is
    // just for this example program and is not needed for CAN operation.
    //
    InitLED();
    
    //
    // 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);

    //
    // wait for the CAN0 module to be ready
    //
    while(!SysCtlPeripheralReady(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() or ui32SysClock 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() or ui32SysClock should be replaced with 
    // 8000000.  Consult the data sheet for more information about CAN 
    // peripheral clocking.
    //
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    CANBitRateSet(CAN0_BASE, ui32SysClock, 500000);
#else
    CANBitRateSet(CAN0_BASE, SysCtlClockGet(), 500000);
#endif

    //
    // 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 a message object to be used for receiving CAN messages with
    // any CAN ID.  In order to receive any CAN ID, the ID and mask must both
    // be set to 0, and the ID filter enabled.
    //
    // sCANMessage.ui32MsgID = 0;
    sCANMessage.ui32MsgID = 1;
    sCANMessage.ui32MsgIDMask = 0;
    sCANMessage.ui32Flags = MSG_OBJ_RX_INT_ENABLE | MSG_OBJ_USE_ID_FILTER;
    //sCANMessage.ui32MsgLen = 8;
    sCANMessage.ui32MsgLen = 4;


    //
    // Now load the message object into the CAN peripheral.  Once loaded the
    // CAN will receive any message on the bus, and an interrupt will occur.
    // Use message object 1 for receiving messages (this is not the same as
    // the CAN ID which can be any value in this example).
    //
    CANMessageSet(CAN0_BASE, 1, &sCANMessage, MSG_OBJ_TYPE_RX);

    //
    // Enter loop to process received messages.  This loop just checks a flag
    // that is set by the interrupt handler, and if set it reads out the
    // message and displays the contents.  This is not a robust method for
    // processing incoming CAN data and can only handle one messages at a time.
    // If many messages are being received close together, 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(;;)
    {
        unsigned int uIdx;

        //
        // If the flag is set, that means that the RX interrupt occurred and
        // there is a message ready to be read from the CAN
        //
        if(g_bRXFlag)
        {
            //
            // 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.
            //
            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_bRXFlag = 0;

            //
            // Check to see if there is an indication that some messages were
            // lost.
            //
            if(sCANMessage.ui32Flags & MSG_OBJ_DATA_LOST)
            {
                //UARTprintf("CAN message loss detected\n");
                printf("CAN message loss detected\n");
                GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, GPIO_PIN_1);
                SimpleDelay(2);
                GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, 0x0);
            }
            else
            {
              GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_3, GPIO_PIN_3);
              SimpleDelay(2);
              GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_3, 0x0); 

            }

            //
            // Print out the contents of the message that was received.
            //
/*
            UARTprintf("Msg ID=0x%08X len=%u data=0x",
                       sCANMessage.ui32MsgID, sCANMessage.ui32MsgLen);
            for(uIdx = 0; uIdx < sCANMessage.ui32MsgLen; uIdx++)
            {
                UARTprintf("%02X ", pui8MsgData[uIdx]);
            }
            UARTprintf("total count=%u\n", g_ui32MsgCount);
*/
            
            printf("Msg ID=0x%08X len=%u data=0x",
                       sCANMessage.ui32MsgID, sCANMessage.ui32MsgLen);
            for(uIdx = 0; uIdx < sCANMessage.ui32MsgLen; uIdx++)
            {
                printf("%02X ", pui8MsgData[uIdx]);
            }
            printf("total count=%u\n", g_ui32MsgCount);
        
        }
                    
        printf("No msg received");
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2);
        SimpleDelay(2);
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0x0); 
    }

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

startup_ewarm.c:

//*****************************************************************************
//
// startup_ewarm.c - Startup code for use with IAR's Embedded Workbench,
//                   version 5.
//
// Copyright (c) 2012-2017 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
// 
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 2.1.4.178 of the EK-TM4C123GXL Firmware Package.
//
//*****************************************************************************

#include <stdint.h>
#include "inc/hw_nvic.h"
#include "inc/hw_types.h"

//*****************************************************************************
//
// Enable the IAR extensions for this source file.
//
//*****************************************************************************
#pragma language=extended

//*****************************************************************************
//
// Forward declaration of the default fault handlers.
//
//*****************************************************************************
void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);

//*****************************************************************************
//
// The entry point for the application startup code.
//
//*****************************************************************************
extern void __iar_program_start(void);

extern void CANIntHandler(void);

//*****************************************************************************
//
// Reserve space for the system stack.
//
//*****************************************************************************
static uint32_t pui32Stack[128] @ ".noinit";

//*****************************************************************************
//
// A union that describes the entries of the vector table.  The union is needed
// since the first entry is the stack pointer and the remainder are function
// pointers.
//
//*****************************************************************************
typedef union
{
    void (*pfnHandler)(void);
    uint32_t ui32Ptr;
}
uVectorEntry;

//*****************************************************************************
//
// The vector table.  Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000.
//
//*****************************************************************************
__root const uVectorEntry __vector_table[] @ ".intvec" =
{
    { .ui32Ptr = (uint32_t)pui32Stack + sizeof(pui32Stack) },
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    IntDefaultHandler,                      // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // SVCall handler
    IntDefaultHandler,                      // Debug monitor handler
    0,                                      // Reserved
    IntDefaultHandler,                      // The PendSV handler
    IntDefaultHandler,                      // The SysTick handler
    IntDefaultHandler,                      // GPIO Port A
    IntDefaultHandler,                      // GPIO Port B
    IntDefaultHandler,                      // GPIO Port C
    IntDefaultHandler,                      // GPIO Port D
    IntDefaultHandler,                      // GPIO Port E
    IntDefaultHandler,                      // UART0 Rx and Tx
    IntDefaultHandler,                      // UART1 Rx and Tx
    IntDefaultHandler,                      // SSI0 Rx and Tx
    IntDefaultHandler,                      // I2C0 Master and Slave
    IntDefaultHandler,                      // PWM Fault
    IntDefaultHandler,                      // PWM Generator 0
    IntDefaultHandler,                      // PWM Generator 1
    IntDefaultHandler,                      // PWM Generator 2
    IntDefaultHandler,                      // Quadrature Encoder 0
    IntDefaultHandler,                      // ADC Sequence 0
    IntDefaultHandler,                      // ADC Sequence 1
    IntDefaultHandler,                      // ADC Sequence 2
    IntDefaultHandler,                      // ADC Sequence 3
    IntDefaultHandler,                      // Watchdog timer
    IntDefaultHandler,                      // Timer 0 subtimer A
    IntDefaultHandler,                      // Timer 0 subtimer B
    IntDefaultHandler,                      // Timer 1 subtimer A
    IntDefaultHandler,                      // Timer 1 subtimer B
    IntDefaultHandler,                      // Timer 2 subtimer A
    IntDefaultHandler,                      // Timer 2 subtimer B
    IntDefaultHandler,                      // Analog Comparator 0
    IntDefaultHandler,                      // Analog Comparator 1
    IntDefaultHandler,                      // Analog Comparator 2
    IntDefaultHandler,                      // System Control (PLL, OSC, BO)
    IntDefaultHandler,                      // FLASH Control
    IntDefaultHandler,                      // GPIO Port F
    IntDefaultHandler,                      // GPIO Port G
    IntDefaultHandler,                      // GPIO Port H
    IntDefaultHandler,                      // UART2 Rx and Tx
    IntDefaultHandler,                      // SSI1 Rx and Tx
    IntDefaultHandler,                      // Timer 3 subtimer A
    IntDefaultHandler,                      // Timer 3 subtimer B
    IntDefaultHandler,                      // I2C1 Master and Slave
    IntDefaultHandler,                      // Quadrature Encoder 1
    //IntDefaultHandler,                      // CAN0
    CANIntHandler,                          // CAN0
    IntDefaultHandler,                      // CAN1
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // Hibernate
    IntDefaultHandler,                      // USB0
    IntDefaultHandler,                      // PWM Generator 3
    IntDefaultHandler,                      // uDMA Software Transfer
    IntDefaultHandler,                      // uDMA Error
    IntDefaultHandler,                      // ADC1 Sequence 0
    IntDefaultHandler,                      // ADC1 Sequence 1
    IntDefaultHandler,                      // ADC1 Sequence 2
    IntDefaultHandler,                      // ADC1 Sequence 3
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // GPIO Port J
    IntDefaultHandler,                      // GPIO Port K
    IntDefaultHandler,                      // GPIO Port L
    IntDefaultHandler,                      // SSI2 Rx and Tx
    IntDefaultHandler,                      // SSI3 Rx and Tx
    IntDefaultHandler,                      // UART3 Rx and Tx
    IntDefaultHandler,                      // UART4 Rx and Tx
    IntDefaultHandler,                      // UART5 Rx and Tx
    IntDefaultHandler,                      // UART6 Rx and Tx
    IntDefaultHandler,                      // UART7 Rx and Tx
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // I2C2 Master and Slave
    IntDefaultHandler,                      // I2C3 Master and Slave
    IntDefaultHandler,                      // Timer 4 subtimer A
    IntDefaultHandler,                      // Timer 4 subtimer B
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // Timer 5 subtimer A
    IntDefaultHandler,                      // Timer 5 subtimer B
    IntDefaultHandler,                      // Wide Timer 0 subtimer A
    IntDefaultHandler,                      // Wide Timer 0 subtimer B
    IntDefaultHandler,                      // Wide Timer 1 subtimer A
    IntDefaultHandler,                      // Wide Timer 1 subtimer B
    IntDefaultHandler,                      // Wide Timer 2 subtimer A
    IntDefaultHandler,                      // Wide Timer 2 subtimer B
    IntDefaultHandler,                      // Wide Timer 3 subtimer A
    IntDefaultHandler,                      // Wide Timer 3 subtimer B
    IntDefaultHandler,                      // Wide Timer 4 subtimer A
    IntDefaultHandler,                      // Wide Timer 4 subtimer B
    IntDefaultHandler,                      // Wide Timer 5 subtimer A
    IntDefaultHandler,                      // Wide Timer 5 subtimer B
    IntDefaultHandler,                      // FPU
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // I2C4 Master and Slave
    IntDefaultHandler,                      // I2C5 Master and Slave
    IntDefaultHandler,                      // GPIO Port M
    IntDefaultHandler,                      // GPIO Port N
    IntDefaultHandler,                      // Quadrature Encoder 2
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // GPIO Port P (Summary or P0)
    IntDefaultHandler,                      // GPIO Port P1
    IntDefaultHandler,                      // GPIO Port P2
    IntDefaultHandler,                      // GPIO Port P3
    IntDefaultHandler,                      // GPIO Port P4
    IntDefaultHandler,                      // GPIO Port P5
    IntDefaultHandler,                      // GPIO Port P6
    IntDefaultHandler,                      // GPIO Port P7
    IntDefaultHandler,                      // GPIO Port Q (Summary or Q0)
    IntDefaultHandler,                      // GPIO Port Q1
    IntDefaultHandler,                      // GPIO Port Q2
    IntDefaultHandler,                      // GPIO Port Q3
    IntDefaultHandler,                      // GPIO Port Q4
    IntDefaultHandler,                      // GPIO Port Q5
    IntDefaultHandler,                      // GPIO Port Q6
    IntDefaultHandler,                      // GPIO Port Q7
    IntDefaultHandler,                      // GPIO Port R
    IntDefaultHandler,                      // GPIO Port S
    IntDefaultHandler,                      // PWM 1 Generator 0
    IntDefaultHandler,                      // PWM 1 Generator 1
    IntDefaultHandler,                      // PWM 1 Generator 2
    IntDefaultHandler,                      // PWM 1 Generator 3
    IntDefaultHandler                       // PWM 1 Fault
};

//*****************************************************************************
//
// This is the code that gets called when the processor first starts execution
// following a reset event.  Only the absolutely necessary set is performed,
// after which the application supplied entry() routine is called.  Any fancy
// actions (such as making decisions based on the reset cause register, and
// resetting the bits in that register) are left solely in the hands of the
// application.
//
//*****************************************************************************
void
ResetISR(void)
{
    //
    // Enable the floating-point unit.  This must be done here to handle the
    // case where main() uses floating-point and the function prologue saves
    // floating-point registers (which will fault if floating-point is not
    // enabled).  Any configuration of the floating-point unit using DriverLib
    // APIs must be done here prior to the floating-point unit being enabled.
    //
    // Note that this does not use DriverLib since it might not be included in
    // this project.
    //
    HWREG(NVIC_CPAC) = ((HWREG(NVIC_CPAC) &
                         ~(NVIC_CPAC_CP10_M | NVIC_CPAC_CP11_M)) |
                        NVIC_CPAC_CP10_FULL | NVIC_CPAC_CP11_FULL);

    //
    // Call the application's entry point.
    //
    __iar_program_start();
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a NMI.  This
// simply enters an infinite loop, preserving the system state for examination
// by a debugger.
//
//*****************************************************************************
static void
NmiSR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
IntDefaultHandler(void)
{
    //
    // Go into an infinite loop.
    //
    while(1)
    {
    }
}

some code changes i have made:

in main.c: 

1. #define PART_TM4C123GH6PM

2. I used LED to show the status (red: error, green: reception successful, blue: no message received) instead of UART because there was error with the functions "UARTStdioConfig()" and "UARTprintf()" ("no definition" but in fact there are)

3. sCANMessage.ui32MsgLen = 4; (instead of the original 8) to match that in the transmission message.

in startup_ewarm.c:

1. interrupt function declare: extern void CANIntHandler(void); (this function is defined in main.c)

2. in verctor table:

     //IntDefaultHandler,                      // CAN0
    CANIntHandler,                          // CAN0

for the communication I have connected the PB4 of reception board with PB5 of transmission board.

my problem is:

the blue led of the reception board always blinks, which means no msg received ( g_bRXFlag=0 ).

(the green led of the transmission board always blinks, meaning that msg transmitted successfully?)

besides, there is a warning "Warning[Lt009]: Inconsistent wchar_t size
            can.o(driverlib.a) and 5 other objects have wchar_t size 16 bits
            main.o and 25 other objects have wchar_t size 32 bits "

i do not know, if  this has effect on it.

Thx a lot.

best regards and happy weekend.

  • Meidan Zhao said:
    for the communication I have connected the PB4 of reception board with PB5 of transmission board.

    Often - by making such "direct connections" (i.e. those w/out benefit of the (standard) CAN Transceiver) CAN commo fails.     This forum reports (some few) who claim to have achieved success - w/out employing the transceivers - yet that is NOT a preferred connection method.

    We have noted that the CAN_TX must be (ordered or pulled high) to insure proper operation.    (the CAN Xcvr provides this "high" - IIRC)

    May I suggest that you "try again" - yet make NO CHANGES to the "Simple RX/TX files" - they are KNOWN to work well - your "mods" must wait until after commo is proven!   (it is ok to replace "Non-CAN" functions - such as your LED substitution for UART - but I urge you to stick w/the KNOWN GOOD (i.e. unaltered) CAN Simple RX/TX code!

    Note too that "adequate power" must arrive - to each of your LPads.     And - you must have attached a common ground - between those 2 boards.    Your order of several CAN Xcvrs can only assist your efforts - "savings - at this time (development) should not trump "conforming to "normal practice" (which demands CAN Xcvrs @ each CAN location.)

  • Hallo cb1_mobile,

    thank you very much for your help and suggestions.

    With the CAN transceiver it works well.
    "adequate power": VBUS.
    Common ground.

    But in my case(IAR Embedded Workbench 8.11) some changes in code are needed.
    1. #define PART_TM4C123GH6PM (otherwise we have to define GPIO port/pin for CAN)
    2. comment out the code with "UARTprintf()" or "UARTStdioConfig()"(otherwise errors because of "no definiton")
    3. in the file "startup_ewarm.c":
    1) interrupt function declaration: "extern void CANIntHandler(void);
    2) in vector table: IntDefaultHandler for CAN0 replaced by CANIntHandler.

    Now everything is fine. Thx again.

    Best regards.
  • Good for you - be proud that you persisted & succeeded.
    Your addition of the "color change @ board's LED" - rather than UART message - was an inventive & efficient improvement - good job...

    Thank you for the "Verify" - my pleasure to assist - yet you did the real work and gained "real learning!"