您好：
我是一個剛開始學習DSP的人，在使用範例程式的eCAN的A to B 輸出時，出現了這樣子的問題，無論如何這個波形都無法改變，例如更改Data或是ID的內容。
請問是否有人可以幫助我。非常感謝
這個波形是透過示波器上的Trigger所的到的
//###########################################################################
//
// FILE: Example_2833xEcanA_to_B_Xmit.c
//
// TITLE: eCAN-A to eCAN-B Transmit Loop Example
//
//! \addtogroup f2833x_example_list
//! <h1>eCAN-A to eCAN-B Transmit Loop (ecan_a_to_b_xmit)</h1>
//!
//! This example TRANSMITS data to another CAN module using MAILBOX5
//! This program could either loop forever or transmit "n" # of times,
//! where "n" is the TXCOUNT value. \n
//!
//! This example can be used to check CAN-A and CAN-B. Since CAN-B is
//! initialized in DSP2833x_ECan.c, it will acknowledge all frames
//! transmitted by the node on which this code runs. Both CAN ports of
//! the 2833x DSP need to be connected to each other (via CAN transceivers)
//!
//! \b External \b Connections \n
//! - eCANA is on GPIO31 (CANTXA) and GPIO30 (CANRXA)
//! - eCANB is on GPIO8 (CANTXB) and GPIO10 (CANRXB)
//! - Connect eCANA to eCANB via CAN transceivers
//
//###########################################################################
// $TI Release: $
// $Release Date: $
// $Copyright:
// Copyright (C) 2009-2024 Texas Instruments Incorporated - http://www.ti.com/
//
// 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.
// $
//###########################################################################
//
// Included Files
//
#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
//
// Defines
//
#define TXCOUNT 100 // Transmission will take place (TXCOUNT) times
//
// Globals
//
long i;
long loopcount = 0;
//
// Main
//
void main(void)
{
//
// Create a shadow register structure for the CAN control registers.
// This is needed, since only 32-bit access is allowed to these registers.
// 16-bit access to these registers could potentially corrupt the register
// contents or return false data.
//
struct ECAN_REGS ECanaShadow;
//
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2833x_SysCtrl.c file.
//
InitSysCtrl();
//
// Step 2. Initialize GPIO:
// This example function is found in the DSP2833x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
//
// InitGpio(); // Skipped for this example
//
// Just initialize eCAN pins for this example
// This function is in DSP2833x_ECan.c
//
InitECanGpio();
//
// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
//
DINT;
//
// Initialize the PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the DSP2833x_PieCtrl.c file.
//
InitPieCtrl();
//
// Disable CPU interrupts and clear all CPU interrupt flags
//
IER = 0x0000;
IFR = 0x0000;
//
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in DSP2833x_DefaultIsr.c.
// This function is found in DSP2833x_PieVect.c.
//
InitPieVectTable();
//
// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.
//
//
// No interrupts used in this example.
//
//
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2833x_InitPeripherals.c
//
// InitPeripherals(); // Not required for this example
//
// In this case just initialize eCAN-A and eCAN-B
// This function is in DSP2833x_ECan.c
//
InitECan();
//
// Step 5. User specific code
//
//
// Write to the MSGID field
//
ECanaMboxes.MBOX25.MSGID.all = 0x95555555; // Extended Identifier
//
// Configure Mailbox under test as a Transmit mailbox
//
ECanaShadow.CANMD.all = ECanaRegs.CANMD.all;
ECanaShadow.CANMD.bit.MD25 = 0;
ECanaRegs.CANMD.all = ECanaShadow.CANMD.all;
//
// Enable Mailbox under test
//
ECanaShadow.CANME.all = ECanaRegs.CANME.all;
ECanaShadow.CANME.bit.ME25 = 1;
ECanaRegs.CANME.all = ECanaShadow.CANME.all;
//
// Write to DLC field in Master Control reg
//
ECanaMboxes.MBOX25.MSGCTRL.bit.DLC = 8;
//
// Write to the mailbox RAM field
//
ECanaMboxes.MBOX25.MDL.all = 0x55555555;
ECanaMboxes.MBOX25.MDH.all = 0x55555555;
//
// Begin transmitting
//
for(i=0; i < TXCOUNT; i++)
{
ECanaShadow.CANTRS.all = 0;
ECanaShadow.CANTRS.bit.TRS25 = 1; // Set TRS for mailbox under test
ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all;
do
{
ECanaShadow.CANTA.all = ECanaRegs.CANTA.all;
} while(ECanaShadow.CANTA.bit.TA25 == 0 );// Wait for TA5 bit to be set
ECanaShadow.CANTA.all = 0;
ECanaShadow.CANTA.bit.TA25 = 1; // Clear TA5
ECanaRegs.CANTA.all = ECanaShadow.CANTA.all;
loopcount ++;
}
__asm(" ESTOP0"); // Stop here
}
//
// End of File
//