McBSP帧同步脉宽设置问题，无法设置低于字长的脉宽

void McBSP_Init(void)
{
McbspaRegs.SPCR2.all=0x0000;
McbspaRegs.SPCR1.all=0x0000;

McbspaRegs.SPCR2.bit.FREE = 1;
McbspaRegs.SPCR2.bit.SOFT = 1; //1x – Free run
McbspaRegs.SPCR2.bit.XINTM = 0; //0 – XINT when XRDY set, indicate the transmitter is ready to accept new data
McbspaRegs.SPCR2.bit.XSYNCERR = 0; //0 – Clear Transmit frame-synch error

McbspaRegs.SPCR1.bit.DLB = 0; //0 – Disable DLB mode. Comment out for non-DLB mode.
McbspaRegs.SPCR1.bit.RJUST = 0; //0 – Right justify the Receive data and Zero fill the MSB
McbspaRegs.SPCR1.bit.CLKSTP = 0x2; //2 – Clock stop mode, without clock delay
McbspaRegs.SPCR1.bit.DXENA = 0; //0 – DX delay enabler off
McbspaRegs.SPCR1.bit.RINTM = 0; //0 – RINT when RRDY set, indicate the receive data is ready to be read
McbspaRegs.SPCR1.bit.RSYNCERR = 0; //0 – Clear Receive frame-synch error

McbspaRegs.MFFINT.all = 0x0; //0 – Disable all interrupts

McbspaRegs.RCR2.bit.RPHASE = 0; //0 – Single-phase frame
McbspaRegs.RCR2.bit.RCOMPAND = 0; //0 – No companding, MSB received first
McbspaRegs.RCR2.bit.RFIG = 1; //0 – Unexpected frame-synch cause aborts data,set RSYNCEERR and begin new data
McbspaRegs.RCR2.bit.RDATDLY = 0; //0 – RX data delay is 0 bit

McbspaRegs.RCR1.bit.RFRLEN1 = 0; //0 – 1 word in phase 1 of the receive frame
McbspaRegs.RCR1.bit.RWDLEN1 = 2; //2 – 16bits, Receive word length

McbspaRegs.XCR2.bit.XPHASE = 0; //0 – Single-phase frame
McbspaRegs.XCR2.bit.XCOMPAND = 0; //0 – No companding, MSB transmit first
McbspaRegs.XCR2.bit.XFIG = 1; //1 – Ignore Transmit Frame-synch
McbspaRegs.XCR2.bit.XDATDLY = 0; //0 – TX data delay is 0 bit

McbspaRegs.XCR1.bit.XFRLEN1 = 0; //0 – 1 word in phase 1 of the transmit frame
McbspaRegs.XCR1.bit.XWDLEN1 = 0; //0 – 8 bits, Transmit word length

McbspaRegs.SRGR2.bit.GSYNC = 0; //0 – No clock sync for CLKG
McbspaRegs.SRGR2.bit.FPER = 11; //11 – Frame-synch period, (11+1)*(1000/1200) = 10ms
McbspaRegs.SRGR2.bit.FSGM = 1; //1 – Frame-synch pulses from the sample rate generator

McbspaRegs.PCR.bit.SCLKME = 1;
McbspaRegs.SRGR2.bit.CLKSM = 0; //1-0 – SCLKME=1, CLKSM=0, Clock Signal on MCLKR pin

McbspaRegs.SRGR1.bit.CLKGDV = 0; //0 – Divide-down value for CLKG 1
delay_loop();
McbspaRegs.SRGR1.bit.FWID = 1; //1 – Frame-synchronization pulse width
delay_loop();

McbspaRegs.PCR.bit.FSXM = 1; //1 – FSX generated internally,
McbspaRegs.PCR.bit.FSRM = 0; //0 – FSR derived from an external source
McbspaRegs.PCR.bit.CLKXM = 1; //1 – CLKX generated internally
McbspaRegs.PCR.bit.CLKRM = 0; //0 – CLKR derived from an external source
McbspaRegs.PCR.bit.FSXP = 0; //0 – Transmit frame-synch pulses are active high
McbspaRegs.PCR.bit.FSRP = 0; //0 – Receive frame-synch pulses are active high
McbspaRegs.PCR.bit.CLKXP = 1; //1 – Transmit data is sampled on the Falling edge of CLKX
McbspaRegs.PCR.bit.CLKRP = 1; //1 – Receive data is sampled on the rising edge of MCLKR

McbspaRegs.SPCR2.bit.GRST = 1; //1 – Enable Sample rate generator
delay_loop(); // wait at least 2 CLKG clock cycles
McbspaRegs.SPCR2.bit.XRST = 1; //1 – Release TX from Reset
McbspaRegs.SPCR1.bit.RRST = 1; //1 – Release RX from Reset
McbspaRegs.SPCR2.bit.FRST = 1; //1 – Frame Sync Generator reset
}