F28035的CAN调试过程中的奇怪问题，请教是何原因。

各位好，我的系统中用到F28035PNT，其中将GPIO30,GPIO31分别配置成CANRXA，CANTXA，然后初始化CANA，配置邮箱，并把装载数据，启动发送后，我在同样的板上测试，有部分F28035的CANTXA引脚有信号，有部分则没有信号。没有信号的板尝试换了IC，还是没有信号，引脚没有虚焊，这有可能是什么问题。 

程序如下：

EALLOW;

GpioCtrlRegs.GPAPUD.bit.GPIO30 = 0; 
GpioCtrlRegs.GPAPUD.bit.GPIO31 = 0; 

GpioCtrlRegs.GPAQSEL2.bit.GPIO30 = 3;

GpioCtrlRegs.GPAMUX2.bit.GPIO30 = 1;

GpioCtrlRegs.GPAMUX2.bit.GPIO31 = 1; 

EDIS;

然后，初始化CAN，程序如下：

struct ECAN_REGS ECanaShadow;

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; 

ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.SCB = 1; // SCB=1 Select eCAN mode.
ECanaShadow.CANMC.bit.MBCC=1; //MBCC=1,Mailbox16成功收发后将时间戳寄存器清0
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

ECanaMboxes.MBOX0.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX1.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX2.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX3.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX4.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX5.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX6.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX7.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX8.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX9.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX10.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX11.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX12.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX13.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX14.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX15.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX16.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX17.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX18.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX19.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX20.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX21.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX22.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX23.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX24.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX25.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX26.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX27.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX28.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX29.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX30.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX31.MSGCTRL.all = 0x00000000;

ECanaRegs.CANTA.all = 0xFFFFFFFF; 

ECanaRegs.CANRMP.all = 0xFFFFFFFF; 

ECanaRegs.CANGIF0.all = 0xFFFFFFFF; 
ECanaRegs.CANGIF1.all = 0xFFFFFFFF;

ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 1 ; 
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

do
{
ECanaShadow.CANES.all = ECanaRegs.CANES.all;
} while(ECanaShadow.CANES.bit.CCE != 1 ); // Wait for CCE bit to be set..

ECanaShadow.CANBTC.all = 0;

ECanaShadow.CANBTC.bit.BRPREG = 29; //TQ=(BRPREG+1)/30 us
ECanaShadow.CANBTC.bit.TSEG2REG = 1; //
ECanaShadow.CANBTC.bit.TSEG1REG = 6; // Bit time=(TSEG2REG+TSEG1REG+3)*TQ
ECanaShadow.CANBTC.bit.SAM = 1;
ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all;

ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 0 ; // Set CCR = 0 修改上面的控制寄存器完成后让CCR=0
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
// 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 ); // Wait for CCE bit to be cleared..
ECanaRegs.CANME.all = 0;
EDIS;

最后配置邮箱

ECanaMboxes.MBOX0.MSGID.all=0x98605601;

ECanaRegs.CANMD.all = 0xFFFF0000; //0:发送, 1:接收

ECanaRegs.CANME.all = 0xFFFFFFFF; //

ECanaMboxes.MBOX0.MSGCTRL.bit.DLC = 2; //数据长度
ECanaMboxes.MBOX0.MSGCTRL.bit.RTR = 0;

ECanaMboxes.MBOX0.MDL.byte.BYTE0=0xaa;
ECanaMboxes.MBOX0.MDL.byte.BYTE1=0x55;

最后，定时触发发送请求。

ECanaRegs.CANTRS.bit.TRS0=1;