Hi Team,
Recently I configured Mcbsp0 as a spi slave, and the relevant register configuration is as follows. (I referred to Section 6.7 of SPRU592E.) The code comment is not accurate, and the DSP receives data on the falling edge of the clock.
MCBSP_Config SPI_SLAVE = {
MCBSP_SPCR1_RMK(
MCBSP_SPCR1_DLB_OFF, /* DLB = 0,禁止自闭环方式 */
MCBSP_SPCR1_RJUST_LZF, /* RJUST = 2,左检验，低位填0*/
MCBSP_SPCR1_CLKSTP_NODELAY, /时停模式无延迟*/
MCBSP_SPCR1_DXENA_NA, /* DXENA = 1,不允许DX数据延迟 */
0, /* ABIS = 0 */
MCBSP_SPCR1_RINTM_FRM, /* RINTM = 0 ,RRDY bit从0到1产生接收中断*/
0, /* RSYNCER = 0,无同步错误*/
MCBSP_SPCR1_RRST_DISABLE /* RRST = 0,串口复位 */
),
MCBSP_SPCR2_RMK(
MCBSP_SPCR2_FREE_NO, /* FREE = 0,时钟受SOFYT bit控制 */
MCBSP_SPCR2_SOFT_NO, /* SOFT = 0,调试出现断点时时钟立即停止 */
//MCBSP_SPCR2_FRST_RESET, //帧同步关闭
MCBSP_SPCR2_FRST_FSG, /* FRST = 0 */
//MCBSP_SPCR2_GRST_RESET, /* GRST = 0,采样率发生器复位，CLKG频率为CPU时钟周期的一半 */
MCBSP_SPCR2_GRST_CLKG,
MCBSP_SPCR2_XINTM_XRDY, /* XINTM = 0,XRDY bit从0到1产生发送中断 */
0, /* XSYNCER = N/A,无同步错误 */
MCBSP_SPCR2_XRST_DISABLE /* XRST = 0,发送串口复位 */
),
/*单数据相，接受数据长度为16位,每相2个数据*/
MCBSP_RCR1_RMK(
MCBSP_RCR1_RFRLEN1_OF(0), /* RFRLEN1 = 0,接收帧每帧一字 */
MCBSP_RCR1_RWDLEN1_16BIT /* RWDLEN1 = 5,每字32位 */
),
MCBSP_RCR2_RMK(
MCBSP_RCR2_RPHASE_SINGLE, /* RPHASE = 0,单段帧 */
MCBSP_RCR2_RFRLEN2_OF(0), /* RFRLEN2 = 0,该帧无字 */
MCBSP_RCR2_RWDLEN2_8BIT, /* RWDLEN2 = 0,每字8bit */
MCBSP_RCR2_RCOMPAND_MSB, /* RCOMPAND = 0,无压缩，先传输高位数据 */
MCBSP_RCR2_RFIG_YES, /* RFIG = 0,每个帧同步信号启动一次数据接收 */
MCBSP_RCR2_RDATDLY_0BIT /* RDATDLY = 1,1bit数据延迟 */
),
MCBSP_XCR1_RMK(
MCBSP_XCR1_XFRLEN1_OF(0), /* XFRLEN1 = 0,发送帧每帧一字 */
MCBSP_XCR1_XWDLEN1_16BIT /* XWDLEN1 = 5,每字32位 */
),
MCBSP_XCR2_RMK(
MCBSP_XCR2_XPHASE_SINGLE, /* XPHASE = 0,单段帧 */
MCBSP_XCR2_XFRLEN2_OF(0), /* XFRLEN2 = 0,该帧无字 */
MCBSP_XCR2_XWDLEN2_8BIT, /* XWDLEN2 = 5,每字32bit */
MCBSP_XCR2_XCOMPAND_MSB, /* XCOMPAND = 0,无压缩，先传输高位数据 */
MCBSP_XCR2_XFIG_YES, /* XFIG = 0,每个帧同步信号启动一次数据发送 */
MCBSP_XCR2_XDATDLY_0BIT /* XDATDLY = 1,1bit数据延迟 */
),
MCBSP_SRGR1_RMK(
MCBSP_SRGR1_FWID_OF(1), /* 停止模式无效**重要FWID = 0 帧同步信号的脉宽周期数*/
MCBSP_SRGR1_CLKGDV_OF(0) /* 停止模式无效**重要CLKGDV =1 CLKG时钟频率*/
),
MCBSP_SRGR2_RMK(
0,//MCBSP_SRGR2_GSYNC_FREE, /* FREE = 0 内部时钟帧同步 （每FPER+1个CLKG周期产生FSG脉冲时钟同步）*/
MCBSP_SRGR2_CLKSP_RISING, /* 重要CLKSP = 0 CLKS 引脚极性，CLKS上升沿产生CLKG和FSG*/
MCBSP_SRGR2_CLKSM_INTERNAL, /* 重要CLKSM = 1 cpu时钟（叠加93行SCLKME=0）*/
MCBSP_SRGR2_FSGM_DXR2XSR, /* FSGM = 0 发送帧同步模式，如果FXSM=1,当DXR->XSR时,McBSP产生帧同步信号*/
MCBSP_SRGR2_FPER_OF(0) /*重要 FPER = 0 FSG信号帧同步时钟周期数，应该是7*（每个FSG周期为FPER+1个CLKG时钟周期）*/
),
MCBSP_MCR1_DEFAULT,
MCBSP_MCR2_DEFAULT,
MCBSP_PCR_RMK(
MCBSP_PCR_IDLEEN_RESET, /* IDLEEN = 0，当PERIPH域idle时MCBSP保持有效 */
MCBSP_PCR_XIOEN_SP, /* XIOEN = 0，CLKX,FSX,DX,CLKS用作串口引脚 */
MCBSP_PCR_RIOEN_SP, /* RIOEN = 0，CLKX,FSX,DX,CLKS用作串口引脚 */
MCBSP_PCR_FSXM_EXTERNAL, /* FSXM = 0，接收帧同步信号 */
MCBSP_PCR_FSRM_EXTERNAL, /* FSRM = 1，接收帧同步信号由MCBSP提供 */
MCBSP_PCR_CLKXM_INPUT, /* CLKXM = 0，MCBSP作为SPI从设备 */
MCBSP_PCR_CLKRM_OUTPUT, /* CLKRM = 0，外部通过CLKR引脚提供接收时钟（叠加27行DLB=0） */
MCBSP_PCR_SCLKME_NO, /*SCLKME =0，CPU时钟（叠加79行CLKSM=1） */
//MCBSP_PCR_CLKSSTAT_0,
MCBSP_PCR_DXSTAT_0, /* DXSTAT = 0，DX引脚设为低电平 */
//MCBSP_PCR_DRSTAT_0, /*DRSTAT =0，DR引脚设为低电平 */
MCBSP_PCR_FSXP_ACTIVELOW, /* FSXP = 1，发送帧同步信号低有效 */
MCBSP_PCR_FSRP_ACTIVELOW, /* FSRP = 1，接收帧同步信号低有效 */
MCBSP_PCR_CLKXP_FALLING, /* CLKXP = 0，CLKX上升沿发送数据 */
MCBSP_PCR_CLKRP_FALLING /* CLKRP = 1，CLKR上升沿接收数据（CLKR输出数据信号时内部CLKR经过转换后送到CLKR引脚） */
/*低电平无效，有延迟，MCBSP在CLKX上升沿之前半个周期发送数据，在CLKR上升沿接收数据*/
),
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
};
I select RINT0 as the interrupt, and the initialization function is as follows.
void IRQInit(void)
{
/* 设置中断向量入口
修改寄存器IVPH，IVPD，重新定义中断向量表*/
IRQ_setVecs((Uint32)(&VECSTART));
/*禁止可屏蔽中断使能*/
old_intm = IRQ_globalDisable();
/*获取中断标号*/
eventId0 = IRQ_EVT_RINT0;
/* 清除外部中断*/
IRQ_clear(eventId0);
/*设置中断向量地址*/
IRQ_plug(eventId0,&transmit_ready);
/*使能外部中断*/
IRQ_enable(eventId0);
/*使能可屏蔽中断*/
IRQ_globalEnable();
}
The interrupt function is as follows.
interrupt void transmit_ready()
{
Uint16 data = 0;
data = slave_rx16();
delay_us(1);
}
Uint16 slave_rx16(void)
{
Uint16 rx = 0;
while(!MCBSP_rrdy(hMcbsp2));
rx=MCBSP_read16(hMcbsp2);
while(!MCBSP_xrdy(hMcbsp2));
MCBSP_write16(hMcbsp2,0x1234);
return rx;
}
I use STM32 as the host to send 16-bit data 0x9898 (1001 1000 1001 1000) cyclically, but DSP will always receive wrong data as shown in the picture below.
In addition, it's curious that when the clkx0 is disconnected from the host, the DSP can still complete the reading (rx = 0x0), and the register receiving the data can work without the main clock. I wonder why.
Could you illustrate it? Thank you in advance.
Kind regards,
Katherine
