spi dma driven.asm

ADI 公司的DSP ADSP21262 EZ-KIT LITE开发板的全部源代码

/* SPI Control Registers                                  */
#define SPICTL  (0x1000)  /* SPI Control Register         */
#define SPIFLG  (0x1001)  /* SPI Flag register            */
#define SPIBAUD (0x1005)  /* SPI baud setup register      */

/* SPI DMA Registers                                      */
#define IISPI   (0x1080)  /* Internal DMA address         */
#define IMSPI   (0x1081)  /* Internal DMA access modifier */
#define CSPI    (0x1082)  /* Number of words to transfers */
#define CPSPI   (0x1083)  /* Points to next DMA parameters*/
#define SPIDMAC (0x1084)  /* SPI DMA control register     */

/*SPICTL bits                                             */
#define TIMOD2  (0x0002)  /* Use DMA for transfers        */
#define DMISO   (0x0020)  /* Disable MISO pin             */
#define WL32    (0x0100)  /* SPI Word Length = 32         */
#define SPIMS   (0x1000)  /* SPI Master if 1, Slave if 0  */
#define SPIEN   (0x4000)  /* SPI Port Enable              */

/*SPIFLG bits                                             */
#define DS0EN   (0x0001)  /* use FLG0 as SPI device-select*/

/*SPIDMAC bits                                            */
#define SPIDEN  (0x0001)  /* enable DMA on the SPI port   */

/* Default buffer size */
#define BUFSIZE 10
/*========================================================*/
/* Source data to be transmitted via SPI DMA              */
.section/dm seg_dmda;
.var src_buf[BUFSIZE]=  0x11111111,
                        0x22222222,
                        0x33333333,
                        0x44444444,
                        0x55555555,
                        0x66666666,
                        0x77777777,
                        0x88888888,
                        0x99999999,
                        0xAAAAAAAA;

/* Application code */
.global _main;
.segment/pm seg_pmco;
_main:

/* Init SPI MASTER TX DMA */
r0=0;
dm(SPICTL)=r0;
dm(SPIFLG)=r0;
dm(SPIDMAC)=r0;

/* set the SPI baud rate to CCLK/4*64 (781.25KHz @ 200MHz)*/
ustat3 = 0x64;
dm(SPIBAUD)=ustat3;

r0=DS0EN;
dm(SPIFLG) = r0;   /*use flag0 as spi device select */

ustat3=src_buf; dm(IISPI)=ustat3;    /* point to 'src_buf'*/
ustat3=LENGTH(src_buf); dm(CSPI)=ustat3; /* count = 256  */
ustat3=1;       dm(IMSPI)=ustat3;    /* step size = 1     */

ustat3 = DMISO|  /* Disable MISO on transfers */
         WL32|   /* 32-bit words */
         SPIMS|  /* Master mode (internal SPICLK) */
         SPIEN|  /* Enable SPI port */
         TIMOD2; /* Initialize SPI port to begin
                    transmitting when DMA is enabled */
dm(SPICTL)=ustat3;

ustat3=SPIDEN;  dm(SPIDMAC)=ustat3;  /* begin DMA         */
/*========================================================*/

_main.end: jump (pc,0);