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- 2013-12-23
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楼主 |
发表于 2013-12-26 11:02:20
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PC机可以识别开发板为USB设备的话USB部分应该没有问题吧,不知道是不是SD的初始化的问题,请原子帮我看看,万分感谢
u8 MSD_Init(void)
{
u32 i = 0;
/* Initialize SPI2 */
SPI_Config();
/* MSD chip select high */
MSD_CS_HIGH();
/* Send dummy byte 0xFF, 10 times with CS high*/
/* rise CS and MOSI for 80 clocks cycles */
for (i = 0; i <= 9; i++)
{
/* Send dummy byte 0xFF */
MSD_WriteByte(DUMMY);
}
/*------------Put MSD in SPI mode--------------*/
/* MSD initialized and set to SPI mode properly */
return (MSD_GoIdleState());
}
void MSD_WriteByte(u8 Data)
{
/* Wait until the transmit buffer is empty */
while (SPI_GetFlagStatus(SPI1, SPI_FLAG_TXE) == RESET);
/* Send the byte */
SPI_SendData(SPI1, Data);
}
FlagStatus SPI_GetFlagStatus(SPI_TypeDef* SPIx, u16 SPI_FLAG)
{
FlagStatus bitstatus = RESET;
/* Check the parameters */
assert_param(IS_SPI_GET_FLAG(SPI_FLAG));
/* Check the status of the specified SPI flag */
if ((SPIx->SR & SPI_FLAG) != (u16)RESET)
{
/* SPI_FLAG is set */
bitstatus = SET;
}
else
{
/* SPI_FLAG is reset */
bitstatus = RESET;
}
/* Return the SPI_FLAG status */
return bitstatus;
}
void SPI_SendData(SPI_TypeDef* SPIx, u16 Data)
{
/* Write in the DR register the data to be sent */
SPIx->DR = Data;
}
u8 MSD_GoIdleState(void)
{
/* MSD chip select low */
MSD_CS_LOW();
/* Send CMD0 (GO_IDLE_STATE) to put MSD in SPI mode */
MSD_SendCmd(MSD_GO_IDLE_STATE, 0, 0x95);
/* Wait for In Idle State Response (R1 Format) equal to 0x01 */
if (MSD_GetResponse(MSD_IN_IDLE_STATE))
{
/* No Idle State Response: return response failue */
return MSD_RESPONSE_FAILURE;
}
/*----------Activates the card initialization process-----------*/
do
{
/* MSD chip select high */
MSD_CS_HIGH();
/* Send Dummy byte 0xFF */
MSD_WriteByte(DUMMY);
/* MSD chip select low */
MSD_CS_LOW();
/* Send CMD1 (Activates the card process) until response equal to 0x0 */
MSD_SendCmd(MSD_SEND_OP_COND, 0, 0xFF);
/* Wait for no error Response (R1 Format) equal to 0x00 */
}
while (MSD_GetResponse(MSD_RESPONSE_NO_ERROR));
/* MSD chip select high */
MSD_CS_HIGH();
/* Send dummy byte 0xFF */
MSD_WriteByte(DUMMY);
return MSD_RESPONSE_NO_ERROR;
} |
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