Posted on July 11, 2018 at 11:56Hi,
I'm currently working on a project that needs to 'Read' a File in SDCARD.
My MCU is STM32H743XI, and the base for the project, I modified the FatFS uSD standalone application example in Cube FW for H7 V1.2.0, for STM32H743I-EVAL board.
I'm not using the Eval board for the project, so what I've done is; remove MFX I/O related codes from BSP sd.c driver file.
I've tested the project on my own board and it worked as expected when I use 2GB SD card, but it failed at f_open() when I use 4GB SD card.
So I searched this forum and found
https://community.st.com/0D50X00009Xkh8DSAR
, and modified SD_InitCard() function in stm32h7xx_hal_sd.c and inserted CMD1 code like below. The Bold line is changed.
static uint32_t SD_InitCard(SD_HandleTypeDef *hsd)
{
HAL_SD_CardCSDTypedef CSD;
uint32_t errorstate = HAL_SD_ERROR_NONE;
uint16_t sd_rca = 1;
/* Check the power State */
if(SDMMC_GetPowerState(hsd->Instance) == 0)
{
/* Power off */
return HAL_SD_ERROR_REQUEST_NOT_APPLICABLE;
}
if(hsd->SdCard.CardType != CARD_SECURED)
{
/* Send CMD2 ALL_SEND_CID */
errorstate = SDMMC_CmdSendCID(hsd->Instance);
if(errorstate != HAL_SD_ERROR_NONE)
{
return errorstate;
}
/* Get Card identification number data */
hsd->CID[0] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP1);
hsd->CID[1] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP2);
hsd->CID[2] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP3);
hsd->CID[3] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP4);
}
if(hsd->SdCard.CardType != CARD_SECURED)
{
/* Send CMD3 SET_REL_ADDR with argument 0 */
/* SD Card publishes its RCA. */
errorstate = SDMMC_CmdSetRelAdd(hsd->Instance, &sd_rca);
if(errorstate != HAL_SD_ERROR_NONE)
{
return errorstate;
}
}
if(hsd->SdCard.CardType != CARD_SECURED)
{
/* Get the SD card RCA */
hsd->SdCard.RelCardAdd = sd_rca;
/* Send CMD9 SEND_CSD with argument as card's RCA */
errorstate = SDMMC_CmdSendCSD(hsd->Instance, (uint32_t)(hsd->SdCard.RelCardAdd << 16U));
if(errorstate != HAL_SD_ERROR_NONE)
{
return errorstate;
}
else
{
/* Get Card Specific Data */
hsd->CSD[0U] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP1);
hsd->CSD[1U] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP2);
hsd->CSD[2U] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP3);
hsd->CSD[3U] = SDMMC_GetResponse(hsd->Instance, SDMMC_RESP4);
}
}
/* Get the Card Class */
hsd->SdCard.Class = (SDMMC_GetResponse(hsd->Instance, SDMMC_RESP2) >> 20);
/* Get CSD parameters */
HAL_SD_GetCardCSD(hsd, &CSD);
/* Select the Card */
errorstate = SDMMC_CmdSelDesel(hsd->Instance, (uint32_t)(((uint32_t)hsd->SdCard.RelCardAdd) << 16));
if(errorstate != HAL_SD_ERROR_NONE)
{
return errorstate;
}
//20180710
SDMMC_CmdOpCondition(hsd->Instance, 0x40000000);//0xC0100000);//0x40000000);//0x00000000);//0x40000000);
/* All cards are initialized */
return HAL_SD_ERROR_NONE;
}
Here's My Questions:
1. After I changed the code, 4GB SD Card works, but total file-read speed has been significantly slowed down.
(It took 70 'seconds' after the debugging, before the modification it took 1 second when I used 2GB SD card.) Can you tell me why?
2. As you can see, I've tested with variety of arguments for CMD1. I know the [30:29] have to be [1:0], but it seems it doesn't matter. I've tried 0, 0xFFFFFFFF, but 4GB SD card still works.I don't understand why.
3. My Previous board used STM32F743NI MCU and I used SDCARD before, and didn't have any trouble with capacity of SD Card I was using. I assumed SD card initialization is not properly working now, but can't see any critical differences between H7 and F7 HAL Library. What should I do to regain the f_read speed using H7 library?
Thank you in advance.
#fatfs #sd-card #stm32h7
