430读sd卡.doc

430读写SD卡 用了Ti读写SD 卡例子，但是URCTL总是为0X20，而且sd发出都是高电平，没有其他响应，不知什么原因，谢谢大家了 看DC版主曾经发表过过一个读写SD卡的程序，不知有没有做过， 发出复位SD卡命令后，收到总为高电平，响应不正确，解决不了啊 void initSPI (void){ UCTL0 = SWRST; // 8-bit SPI Master **SWRST** UTCTL0 = CKPH | SSEL1 | SSEL0 | STC; // SMCLK, 3-pin mode, clock idle low, data valid on rising edge, UCLK delayed UBR00 = 0x20; // 0x02: UCLK/2 (4 MHz), works also with 3 and 4 UBR10 = 0x00; // -- UMCTL0 = 0x00; // no modulation UCTL0 = CHAR | SYNC | MM | SWRST; // 8-bit SPI Master **SWRST** UCTL0 = ~SWRST; // clear SWRST ME1 |= USPIE0; // Enable USART1 SPI mode while (!(IFG1 UTXIFG0)); // USART1 TX buffer ready (empty)?}// Initialize MMC cardchar initMMC (void){ //raise SS and MOSI for 80 clock cycles //SendByte(0xff) 10 times with SS high //RAISE SS int i; // Port 3 Function Dir On/Off // 3.0-mmcCD Out 0 - card inserted // 3.1-Dout Out 0 - off 1 - On - init in SPI_Init // 3.2-Din Inp 0 - off 1 - On - init in SPI_Init // 3.3-Clk Out - - init in SPI_Init // 2.6-mmcCS Out 0 - Active 1 - none Active  P2DIR |= BIT6; P3SEL |= 0x0E; P3SEL = ~0x11; P3OUT |= 0x10; P3DIR |= 0x0A; initSPI(); //initialization sequence on PowerUp CS_LOW(); for(i=0;i10;i++) spiSendByte(0xff); CS_HIGH(); for(i=0;i=9;i++) spiSendByte(0xff); return (mmc_GoIdle());}char mmc_GoIdle(void){ char response=0x01; CS_LOW(); //Send Command 0 to put MMC in SPI mode mmcSendCmd(MMC_GO_IDLE_STATE,0,0x95); //Now wait for READY RESPONSE if(mmcGetResponse()!=0x00)//应该是收到响应R1，也就是0，可是我总是收到是高电平，也不知是不是太快了，没收到，示波器看了，没有低电平的产生 return MMC_INIT_ERROR; while(response==0x00)