运行CSL库文件中的mcbsp的例程显示TEST FAILED

（附件中顺便附上了整个工程代码）

主程序源码如下：

/*
* Copyright (C) 2003 Texas Instruments Incorporated
* All Rights Reserved
*/
/*
*---------main_mcbsp1.c---------
* In this example, the MCBSP is configured in digital loopback
* mode, with 32 bit data transfer, in multi-frame mode, using
* sample rate generator to sync frames
*/
#include <stdio.h>

#include <csl.h>
#include <csl_mcbsp.h>
#include <csl_irq.h>

//---------Global constants---------
#define N 10

//---------Global data definition---------

MCBSP_Config ConfigLoopBack32= {
MCBSP_SPCR1_RMK(
MCBSP_SPCR1_DLB_ON, /* DLB = 1 */
MCBSP_SPCR1_RJUST_RZF, /* RJUST = 0 */
MCBSP_SPCR1_CLKSTP_DISABLE, /* CLKSTP = 0 */
MCBSP_SPCR1_DXENA_NA, /* DXENA = 0 */
MCBSP_SPCR1_ABIS_DISABLE, /* ABIS = 0 */
MCBSP_SPCR1_RINTM_RRDY, /* RINTM = 0 */
0, /* RSYNCER = 0 */
MCBSP_SPCR1_RRST_DISABLE /* RRST = 0 */
),
MCBSP_SPCR2_RMK(
MCBSP_SPCR2_FREE_NO, /* FREE = 0 */
MCBSP_SPCR2_SOFT_NO, /* SOFT = 0 */
MCBSP_SPCR2_FRST_RESET, /* FRST = 0 */
MCBSP_SPCR2_GRST_RESET, /* GRST = 0 */
MCBSP_SPCR2_XINTM_XRDY, /* XINTM = 0 */
0, /* XSYNCER = N/A */
MCBSP_SPCR2_XRST_DISABLE /* XRST = 0 */
),
MCBSP_RCR1_RMK(
MCBSP_RCR1_RFRLEN1_OF(0), /* RFRLEN1 = 0 */
MCBSP_RCR1_RWDLEN1_32BIT /* RWDLEN1 = 5 */
),
MCBSP_RCR2_RMK(
MCBSP_RCR2_RPHASE_SINGLE, /* RPHASE = 0 */
MCBSP_RCR2_RFRLEN2_OF(0), /* RFRLEN2 = 0 */
MCBSP_RCR2_RWDLEN2_8BIT, /* RWDLEN2 = 0 */
MCBSP_RCR2_RCOMPAND_MSB, /* RCOMPAND = 0 */
MCBSP_RCR2_RFIG_YES, /* RFIG = 0 */
MCBSP_RCR2_RDATDLY_2BIT /* RDATDLY = 0 */
),
MCBSP_XCR1_RMK(
MCBSP_XCR1_XFRLEN1_OF(0), /* XFRLEN1 = 0 */
MCBSP_XCR1_XWDLEN1_32BIT /* XWDLEN1 = 5 */

),
MCBSP_XCR2_RMK(
MCBSP_XCR2_XPHASE_SINGLE, /* XPHASE = 0 */
MCBSP_XCR2_XFRLEN2_OF(0), /* XFRLEN2 = 0 */
MCBSP_XCR2_XWDLEN2_8BIT, /* XWDLEN2 = 0 */
MCBSP_XCR2_XCOMPAND_MSB, /* XCOMPAND = 0 */
MCBSP_XCR2_XFIG_YES, /* XFIG = 0 */
MCBSP_XCR2_XDATDLY_2BIT /* XDATDLY = 0 */
),
MCBSP_SRGR1_RMK(
MCBSP_SRGR1_FWID_OF(1), /* FWID = 1 */
MCBSP_SRGR1_CLKGDV_OF(1) /* CLKGDV = 1 */
),
MCBSP_SRGR2_RMK(
MCBSP_SRGR2_GSYNC_FREE, /* FREE = 0 */
MCBSP_SRGR2_CLKSP_RISING, /* CLKSP = 0 */
MCBSP_SRGR2_CLKSM_INTERNAL, /* CLKSM = 1 */
MCBSP_SRGR2_FSGM_DXR2XSR, /* FSGM = 0 */
MCBSP_SRGR2_FPER_OF(15) /* FPER = 0 */
),
MCBSP_MCR1_DEFAULT,
MCBSP_MCR2_DEFAULT,
MCBSP_PCR_RMK(
MCBSP_PCR_IDLEEN_RESET, /* IDLEEN = 0 */
MCBSP_PCR_XIOEN_SP, /* XIOEN = 0 */
MCBSP_PCR_RIOEN_SP, /* RIOEN = 0 */
MCBSP_PCR_FSXM_INTERNAL, /* FSXM = 1 */
MCBSP_PCR_FSRM_EXTERNAL, /* FSRM = 0 */
MCBSP_PCR_CLKXM_OUTPUT, /* CLKXM = 1 */
MCBSP_PCR_CLKRM_INPUT, /* CLKRM = 0 */
MCBSP_PCR_SCLKME_NO, /* SCLKME = 0 */
0, /* DXSTAT = N/A */
MCBSP_PCR_FSXP_ACTIVEHIGH, /* FSXP = 0 */
MCBSP_PCR_FSRP_ACTIVEHIGH, /* FSRP = 0 */
MCBSP_PCR_CLKXP_RISING, /* CLKXP = 0 */
MCBSP_PCR_CLKRP_FALLING /* CLKRP = 0 */
),
MCBSP_RCERA_DEFAULT,
MCBSP_RCERB_DEFAULT,
MCBSP_RCERC_DEFAULT,
MCBSP_RCERD_DEFAULT,
MCBSP_RCERE_DEFAULT,
MCBSP_RCERF_DEFAULT,
MCBSP_RCERG_DEFAULT,
MCBSP_RCERH_DEFAULT,
MCBSP_XCERA_DEFAULT,
MCBSP_XCERB_DEFAULT,
MCBSP_XCERC_DEFAULT,
MCBSP_XCERD_DEFAULT,
MCBSP_XCERE_DEFAULT,
MCBSP_XCERF_DEFAULT,
MCBSP_XCERG_DEFAULT,
MCBSP_XCERH_DEFAULT
};

/* Define a MCBSP_Handle object to be used with MCBSP_open function */
MCBSP_Handle mhMcbsp;
Uint32 xmt[N], rcv[N];
volatile Uint16 XfrCnt = 0;
Uint16 err = 0;
Uint16 old_intm;
Uint16 rcvEventId, xmtEventId;

//---------Function prototypes---------

/* Reference start of interrupt vector table */
/* This symbol is defined in file, vectors.s55 */
extern void VECSTART(void);

// Interrupt Service Routine Prototypes
interrupt void writeIsr(void);
interrupt void readIsr(void);

void taskFxn(void);

//---------main routine---------
void main(void)
{
Uint16 i;

/* Initialize CSL library - This is REQUIRED !!! */
CSL_init();

/* Set IVPD/IVPH to start of interrupt vector location */
printf("%d\n", &VECSTART);
IRQ_setVecs((Uint32)(&VECSTART));

for (i = 0; i <= N - 1; i++) {
xmt[i] = ((Uint32)i << 17) + i;
rcv[i] = 0;
}

/* Call function to effect transfer */
taskFxn();
}

void taskFxn(void)
{
Uint16 i;

old_intm = IRQ_globalDisable();

/* Open MCBSP Port 0 and set registers to their power on defaults */
mhMcbsp = MCBSP_open(MCBSP_PORT0, MCBSP_OPEN_RESET);

/* Get EventId's associated with MCBSP Port 0 receive and transmit */
/* The event Id's are used to communicate with the CSL interrupt */
/* module functions. */
rcvEventId = MCBSP_getRcvEventId(mhMcbsp);
xmtEventId = MCBSP_getXmtEventId(mhMcbsp);

/* Clear any pending receive or transmit interrupts */
IRQ_clear(rcvEventId);
IRQ_clear(xmtEventId);

/* Place address of interrupt service routines at */
/* associated vector location */
IRQ_plug(rcvEventId, *readIsr);
IRQ_plug(xmtEventId, *writeIsr);

/* Write values from configuration structure to MCBSP control regs */
MCBSP_config(mhMcbsp, &ConfigLoopBack32);

/* Enable the MCBSP receive and transmit interrupts */
IRQ_enable(rcvEventId);
IRQ_enable(xmtEventId);

/* Start Sample Rate Generator and Frame Sync */
MCBSP_start(mhMcbsp,
MCBSP_SRGR_START | MCBSP_SRGR_FRAMESYNC,
0x300
);

/* Enable MCBSP transmit and receive */
MCBSP_start(mhMcbsp,
MCBSP_RCV_START | MCBSP_XMIT_START,
0
);

/* Prime MCBSP transmit */
while(!MCBSP_xrdy(mhMcbsp)){
;
}
MCBSP_write32(mhMcbsp,xmt[XfrCnt]);

/* Enable all masked interrupts */
IRQ_globalEnable();

/* Wait for transfer of data */
while (XfrCnt < 10) {
;
}

/*------------------------------------------*\
* Compare values
\*------------------------------------------*/
for(i = 0; i <= N - 1; i++){
if (rcv[i] != xmt[i]){
++err;
break;
}
}

printf ("%s\n",err?"TEST FAILED" : "TEST PASSED");

/* Restore old value of INTM */
IRQ_globalRestore(old_intm);

/* We're done with MCBSP, so close it */
MCBSP_close(mhMcbsp);
}

interrupt void writeIsr(void)
{
/*
* Disable this ISR's interrupt before the write to the McBSP
* since another interrupt will be generated as soon as the write
* completes, which happens very quickly due to the loopback to
* the McBSP receive.
*/
IRQ_disable(xmtEventId);
MCBSP_write32(mhMcbsp,xmt[XfrCnt]);
}

interrupt void readIsr(void)
{
rcv[XfrCnt] = MCBSP_read32(mhMcbsp);
++XfrCnt;

if (XfrCnt == N) {
IRQ_disable(rcvEventId);
IRQ_disable(xmtEventId);
MCBSP_reset(mhMcbsp);
}
else {
IRQ_enable(xmtEventId);
}
}

经过调试发现，在第二次数据传送过程中，发数据中断服务函数（黄色）并没有执行，而是直接执行了收数据中断服务函数（绿色），所以收端的第二个数据有误（如下图所示）

哪位大神知道这是为什么吗？