Posted on September 22, 2016 at 18:18Sir,
You did not precise the version of the drivers / STM32cube you are using . Is-It the last version ?
I am using the code demonstration code which has came with the product and i'am not using the STM32 cubemx.
In main header i have found the details below
* @file main.c
* @author MCD Application Team
* @version V1.0.1
* @date 25-June-2015
* @brief This file provides main program functions
here i have given the below code i have tried in tat you can see the ''
uint8_t buffer[512];
''
that declared inside the main which leads to read null data at SD read output at DMA mode.
The problem solves if it declared above main i.e Global to main function why this happens ?.
01.
int
main(
void
)
02.
{
03.
/* Configure the MPU attributes as Write Through */
04.
MPU_Config();
05.
/* Enable the CPU Cache */
06.
CPU_CACHE_Enable();
07.
/* STM32F7xx HAL library initialization:
08.
- Configure the Flash ART accelerator on ITCM interface
09.
- Configure the Systick to generate an interrupt each 1 msec
10.
- Set NVIC Group Priority to 4
11.
- Global MSP (MCU Support Package) initialization
12.
*/
13.
HAL_Init();
14.
SystemClock_Config();
15.
BSP_LED_Init(LED1);
16.
BSP_LED_Off(LED1);
17.
uartInit();
18.
SDdetectInit();
19.
BSP_SD_Init();
20.
21.
uint8_t buffer[512];
22.
uint32_t count =63;
23.
24.
HAL_Delay(500);
25.
26.
27.
if
( BSP_SD_ReadBlocks_DMA((uint32_t*)buffer,(uint64_t) (512L*count), (uint32_t) 512, (uint32_t) 1) != MSD_OK)
28.
{
29.
HAL_UART_Transmit(&UartHandle,
''Read failed''
,
sizeof
(
''Read failed''
),500);
30.
}
31.
else
32.
{
33.
HAL_UART_Transmit(&UartHandle,buffer,512,500);
34.
}
similarly i have problem when i have interfaced with FAT FS it was not working It gives DMA readout timer expires.
01.
void
fatfile_read(
void
)
02.
{
03.
04.
FRESULT res;
/* FatFs function common result code */
05.
uint32_t byteswritten, bytesread;
/* File write/read counts */
06.
if
(FATFS_LinkDriver(&SD_Driver, SDPath) == 0)
07.
{
08.
if
(f_mount(&SDFatFs, (TCHAR
const
*)SDPath, 0) != FR_OK)
09.
{
10.
Error_Handler();
11.
}
12.
else
13.
{
14.
if
(f_open(&MyFile,
''STM32.TXT''
, FA_READ) != FR_OK)
15.
{
16.
Error_Handler();
17.
}
18.
else
19.
{
20.
res = f_read(&MyFile, rtext,
sizeof
(rtext), (UINT*)&bytesread);
21.
getStringFromWord(rtext,bytesread);
22.
if
((bytesread == 0) || (res != FR_OK))
23.
{
24.
25.
}
26.
else
27.
{
28.
29.
}
30.
}
31.
f_close(&MyFile);
32.
}
33.
}
34.
// FATFS_UnLinkDriver(SDPath);
35.
36.
}
And fatfs was not working with DMA.
Thanks and regards
Rajesh
