本文介绍了DSP2812微控制器中eCAN模块的初始化过程及通过eCAN发送消息的具体实现。主要内容包括禁用看门狗、配置时钟、初始化锁相环等步骤，并提供了完整的初始化代码示例。此外，还详细展示了如何配置eCAN进行自测模式的消息发送。
DSP2812的采用ecan模块通信发送消息的文件源码(可以实现消息的发送)
作者：61IC 文章来源：本站原创 点击数1237 更新时间：2007-1-16 21:22:20 文章录入：admin 责任编辑：admin
//* file name: CANinit.c
// 本文件是用于初始化 CAN 模块
#include "DSP281x_Device.h"
void DisableDog(void)
{
EALLOW;
SysCtrlRegs.WDCR= 0x0068;//禁止看门狗，并使看门狗时钟为晶振时钟的1/512。
/*---------------------------------------------------------------------------------
WDCR:Watchdog control register bit definitions
bit 15-8 00000000: reserved
bit 7 0: WDFLAG---看门狗复位状态标志位，如果该位置1，表示
看门狗复位满足了条件；如果等于0，表示是上电
复位条件或外部器件复位条件；写1可以将该位清零
bit 6 1: WDDIS----写1，屏蔽看门狗；写0，使能看门狗。只有当SCSR2的
WDOVERRIDE位等于1时，才能改变WDDIS的值，
器件复位后看门狗模块被使能
bit 5-3 101: WDCHK----WDCHK必须写101，写其他值都会引起器件内核复位
bit 2-0 000: WDPS-----配置看门狗计数时钟（WDCLK）相对于OSCCLK/512的倍率
000-WDCLK=OSCCLK/512/1 001- WDCLK=OSCCLK/512/1
010-WDCLK=OSCCLK/512/2 011- WDCLK=OSCCLK/512/4
100-WDCLK=OSCCLK/512/8 101- WDCLK=OSCCLK/512/16
110-WDCLK=OSCCLK/512/32 111- WDCLK=OSCCLK/512/64
----------------------------------------------------------------------------------*/
EDIS;
}
//--------------------------------------------------------------------------
// Example: InitPeripheralClocks:
//---------------------------------------------------------------------------
// This function initializes the clocks to the peripheral modules.
// First the high and low clock prescalers are set
// Second the clocks are enabled to each peripheral.
// To reduce power, leave clocks to unused peripherals disabled
// Note: If a peripherals clock is not enabled then you cannot
// read or write to the registers for that peripheral
void InitPeripheralClocks(void)
{
EALLOW;
// HISPCP/LOSPCP prescale register settings, normally it will be set to default values
SysCtrlRegs.HISPCP.all = 0x0001; //配置高速外设时钟相对于SYSCLKOUT的1/2
/*-------------------------------------------------------------------------
HISPCP:高速外设时钟寄存器，配置高速外设时钟相对于SYSCLKOUT的倍频系数
bit 15-3: reserved
bit 2-0: 000-高速时钟=SYSCLKOUT/1 001-高速时钟=SYSCLKOUT/2(复位时默认)
010-高速时钟=SYSCLKOUT/4 011-高速时钟=SYSCLKOUT/6
100-高速时钟=SYSCLKOUT/8 101-高速时钟=SYSCLKOUT/10
110-高速时钟=SYSCLKOUT/12 111-高速时钟=SYSCLKOUT/14
---------------------------------------------------------------------------*/
SysCtrlRegs.LOSPCP.all = 0x0002;
/*-------------------------------------------------------------------------
LOSPCP:低速外设时钟寄存器，配置低速外设时钟相对于SYSCLKOUT的倍频系数
bit 15-3: reserved
bit 2-0: 000-低速时钟=SYSCLKOUT/1 001-低速时钟=SYSCLKOUT/2(复位时默认)
010-低速时钟=SYSCLKOUT/4 011-低速时钟=SYSCLKOUT/6
100-低速时钟=SYSCLKOUT/8 101-低速时钟=SYSCLKOUT/10
110-低速时钟=SYSCLKOUT/12 111-低速时钟=SYSCLKOUT/14
---------------------------------------------------------------------------*/
// Peripheral clock enables set for the selected peripherals.
SysCtrlRegs.PCLKCR.bit.EVAENCLK=1; //使能EV-A外设内部的高速时钟。对于低功耗模式，可以通过软件或者复位清零
SysCtrlRegs.PCLKCR.bit.EVBENCLK=1; //使能EV-B外设内部的高速时钟?
SysCtrlRegs.PCLKCR.bit.SCIAENCLK=1; //使能SCI-A外设内部的低速时钟?
SysCtrlRegs.PCLKCR.bit.SCIBENCLK=1; //使能SCI-B外设内部的低速时钟?
SysCtrlRegs.PCLKCR.bit.MCBSPENCLK=1;//使能McBSP外设内部的低速时钟?
SysCtrlRegs.PCLKCR.bit.SPIENCLK=1; //使能SPI外设内部的低速时钟?
SysCtrlRegs.PCLKCR.bit.ECANENCLK=1; //使能CAN总线的系统时钟?
SysCtrlRegs.PCLKCR.bit.ADCENCLK=1; //使能ADC外设内部的高速时钟?
EDIS;
}
//---------------------------------------------------------------------------
// Example: InitPll:
//---------------------------------------------------------------------------
// This function initializes the PLLCR register.
void InitPll(Uint16 val)
{
volatile Uint16 iVol;
if (SysCtrlRegs.PLLCR.bit.DIV != val)
{
EALLOW;
SysCtrlRegs.PLLCR.bit.DIV = val;
/*DIV是PLLCR的3-0bit。
DIV=0000，CLKIN=OSCCLK/2; DIV=0001，CLKIN=(OSCCLK*1.0)/2;
DIV=0010，CLKIN=(OSCCLK*2.0)/2; DIV=0011，CLKIN=(OSCCLK*3.0)/2;
DIV=0100，CLKIN=(OSCCLK*4.0)/2; DIV=0101，CLKIN=(OSCCLK*5.0)/2;
DIV=0110，CLKIN=(OSCCLK*6.0)/2; DIV=0111，CLKIN=(OSCCLK*7.0)/2;
DIV=1000，CLKIN=(OSCCLK*8.0)/2; DIV=1001，CLKIN=(OSCCLK*9.0)/2;
DIV=1010，CLKIN=(OSCCLK*10.0)/2; DIV=1011,1100,1101,1110,1111,保留
-----------------------------------------------------------------*/
EDIS;
// Optional: Wait for PLL to lock.
// During this time the CPU will switch to OSCCLK/2 until the PLL is
// stable. Once the PLL is stable the CPU will switch to the new PLL value.
//
// This switch time is 131072 CLKIN cycles as of Rev C silicon.
//
// Code is not required to sit and wait for the PLL to lock.
// However, if the code does anything that is timing critical,
// and requires the correct clock be locked, then it is best to
// wait until this switching has completed.
// If this function is run from waitstated memory, then the loop count can
// be reduced as long as the minimum switch time is still met.
// iVol is volatile so the compiler will not optimize this loop out
//
// The watchdog should be disabled before this loop, or fed within
// the loop.
DisableDog();
// Wait lock cycles.
// Note, This loop is tuned to 0-waitstate RAM memory. If this
// function is run from wait-stated memory such as Flash or XINTF,
// then the number of times through the loop can be reduced
// accordingly.
for(iVol= 0; iVol< ( (131072/2)/12 ); iVol++)
{
}
}
}
void InitEcan(void)
{
long i;
struct ECAN_REGS ECanaShadow;
asm(" EALLOW");
DisableDog(); //屏蔽看门狗
InitPeripheralClocks(); //初始化外设时钟
InitPll(0xA); //设置锁相环的倍频系数
for(i=0;i<100000;i++)
{
asm(" NOP");
}
// For this example, configure CAN pins using GPIO regs here
EALLOW;
GpioMuxRegs.GPFMUX.bit.CANTXA_GPIOF6 = 1;
GpioMuxRegs.GPFMUX.bit.CANRXA_GPIOF7 = 1;
EDIS;
// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
DINT;
// Initialize 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 DSP281x_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 DSP281x_DefaultIsr.c.
// This function is found in DSP281x_PieVect.c.
InitPieVectTable();
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP281x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
// Configure the eCAN RX and TX pins for eCAN transmissions
EALLOW;
ECanaShadow.CANTIOC.all = ECanaRegs.CANTIOC.all;
ECanaShadow.CANTIOC.bit.TXFUNC = 1;
ECanaRegs.CANTIOC.all = ECanaShadow.CANTIOC.all;
ECanaShadow.CANRIOC.all = ECanaRegs.CANRIOC.all;
ECanaShadow.CANRIOC.bit.RXFUNC = 1;
ECanaRegs.CANRIOC.all = ECanaShadow.CANRIOC.all;
EDIS;
EALLOW;
ECanaRegs.CANMIM.all=0xFFFFFFFF;
// Request permission to change the configuration registers
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 1;
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
EDIS;
// Wait until the CPU has been granted permission to change the
// configuration registers
// Wait for CCE bit to be set..
do
{
ECanaShadow.CANES.all = ECanaRegs.CANES.all;
} while(ECanaShadow.CANES.bit.CCE != 1 );
// Configure the eCAN timing
EALLOW;
ECanaShadow.CANBTC.all = ECanaRegs.CANBTC.all;
ECanaShadow.CANBTC.bit.BRPREG = 9; // (BRPREG + 1) = 10 feeds a 15 MHz CAN clock
ECanaShadow.CANBTC.bit.TSEG2REG = 5 ; // to the CAN module. (150 / 10 = 15)
ECanaShadow.CANBTC.bit.TSEG1REG = 7; // Bit time = 15
ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all;
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 0;
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
EDIS;
// Wait until the CPU no longer has permission to change the
// configuration registers
do
{
ECanaShadow.CANES.all = ECanaRegs.CANES.all;
} while(ECanaShadow.CANES.bit.CCE != 0 );
// Configure the eCAN for self test mode
// Enable the enhanced features of the eCAN.
EALLOW;
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.STM = 0; // Configure CAN for self-test mode
ECanaShadow.CANMC.bit.SCB = 1; // eCAN mode (reqd to access 32 mailboxes)
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
EDIS;
// Disable all Mailboxes
// Since this write is to the entire register (instead of a bit
// field) a shadow register is not required.
ECanaRegs.CANME.all = 0;
}
================================================================
================================================================
//FILE NAME:TXLOOP1.C
// 用于发送邮箱信息
/*============================================*/
#include "DSP281x_Device.h"
#define TXCOUNT 10000
long loopcount=0;
void InitEcan(void);
void main()
{
struct ECAN_REGS ECanaShadow;
long i=0;
InitEcan();
ECanaShadow.CANTRR.all=ECanaRegs.CANTRR.all;
ECanaShadow.CANTRR.bit.TRR5=1;
ECanaRegs.CANTRR.all=ECanaShadow.CANTRR.all;
do
{
ECanaShadow.CANTRS.all=ECanaRegs.CANTRS.all;
}while(ECanaShadow.CANTRS.bit.TRS5==1);
ECanaShadow.CANME.all=ECanaRegs.CANME.all;
ECanaShadow.CANME.bit.ME5=0;
ECanaRegs.CANME.all=ECanaShadow.CANME.all;
ECanaMboxes.MBOX5.MSGCTRL.bit.RTR=0;
ECanaMboxes.MBOX5.MSGCTRL.bit.DLC=8;
ECanaMboxes.MBOX5.MSGID.all=0x00140000;
ECanaShadow.CANMD.all=ECanaRegs.CANMD.all;
ECanaShadow.CANMD.bit.MD5=0;
ECanaRegs.CANMD.all=ECanaShadow.CANMD.all;
ECanaShadow.CANME.all=ECanaRegs.CANME.all;
ECanaShadow.CANME.bit.ME5=1;
ECanaRegs.CANME.all=ECanaShadow.CANME.all;
ECanaMboxes.MBOX5.MDL.all=0x01234567;
ECanaMboxes.MBOX5.MDH.all=0x89ABCDEF;
//for(i=0;i<TXCOUNT;i++)
while(1)
{
ECanaShadow.CANTRS.all=ECanaRegs.CANTRS.all;
ECanaShadow.CANTRS.all=0;
ECanaShadow.CANTRS.bit.TRS5=1;
ECanaRegs.CANTRS.all=ECanaShadow.CANTRS.all;
do
{
ECanaShadow.CANTA.all=ECanaRegs.CANTA.all;
}while(ECanaShadow.CANTA.bit.TA5!=1);
ECanaShadow.CANTA.bit.TA5=1;
ECanaRegs.CANTA.all=ECanaShadow.CANTA.all;
loopcount++;
}
}
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