Solved
Reading 8 bit arrays from external SDRAM in STM32H7 gives corrupt data
We are using STM32H745I-DISCO which has a 16 MByte SDRAM. We can read and write 32 and 16 bit values but when we try to read 8 byte arrays we get corrupt data and do not understand how to fix it.
// -------------------------------- TEST CODE
// t1 struct is placed in external memory (code works when put in RAM_D2 but no external ram
void SDRAM_Test8()
{
int result = 1, i;
uint32_t adressStart = 0;
for(adressStart; adressStart < (8*1024*1024-(BUFFER_SIZE8*4)); adressStart += BUFFER_SIZE8)
{
/* Fill the buffer to write */
Fill_Buffer8(t1.aTxBuffer8, BUFFER_SIZE8, 0x00);
/* Fill the Read buffer */
memset(t1.aRxBuffer8,0,BUFFER_SIZE8);
for (i = 0; i < BUFFER_SIZE8; i++)
{
*(__IO uint8_t*) (SDRAM_BANK_ADDR + i + adressStart) = t1.aTxBuffer8[i];
}
for (i = 0; i < BUFFER_SIZE8; i++)
{
t1.aRxBuffer8[i] = *(__IO uint8_t*) (SDRAM_BANK_ADDR + i + adressStart);
}
for (i = 0; i < BUFFER_SIZE8; i++)
{
if (t1.aRxBuffer8[i] != t1.aTxBuffer8[i])
{
result = 0;
break;
}
}
}
void MPU_Config(void)
{
MPU_Region_InitTypeDef MPU_InitStruct;
/* Disable the MPU */
HAL_MPU_Disable();
/* Configure the MPU as Strongly ordered for not defined regions */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x00;
MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER0;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x87;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Configure the MPU attributes as WT for SDRAM */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = SDRAM_BANK_ADDR;
MPU_InitStruct.Size = MPU_REGION_SIZE_16MB;
MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER1;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x00;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
HAL_MPU_ConfigRegion(&MPU_InitStruct);
/* Enable the MPU */
HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
/* Enable the CPU Cache */
CPU_CACHE_Enable();
}
void SDRAM_Init()
{
/*##-1- Configure the SDRAM device #########################################*/
/* SDRAM device configuration */
hsdram.Instance = FMC_SDRAM_DEVICE;
/* Timing configuration */
SDRAM_Timing.LoadToActiveDelay = 2;
SDRAM_Timing.ExitSelfRefreshDelay = 7;
SDRAM_Timing.SelfRefreshTime = 4;
SDRAM_Timing.RowCycleDelay = 7;
SDRAM_Timing.WriteRecoveryTime = 2;
SDRAM_Timing.RPDelay = 2;
SDRAM_Timing.RCDDelay = 2;
hsdram.Init.SDBank = FMC_SDRAM_BANK2;
hsdram.Init.ColumnBitsNumber = FMC_SDRAM_COLUMN_BITS_NUM_8;
hsdram.Init.RowBitsNumber = FMC_SDRAM_ROW_BITS_NUM_12;
hsdram.Init.MemoryDataWidth = SDRAM_MEMORY_WIDTH;
hsdram.Init.InternalBankNumber = FMC_SDRAM_INTERN_BANKS_NUM_4;
hsdram.Init.CASLatency = FMC_SDRAM_CAS_LATENCY_3;
hsdram.Init.WriteProtection = FMC_SDRAM_WRITE_PROTECTION_DISABLE;
hsdram.Init.SDClockPeriod = SDCLOCK_PERIOD;
hsdram.Init.ReadBurst = FMC_SDRAM_RBURST_ENABLE;
hsdram.Init.ReadPipeDelay = FMC_SDRAM_RPIPE_DELAY_2;
/* Initialize the SDRAM controller */
if(HAL_SDRAM_Init(&hsdram, &SDRAM_Timing) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
/* Program the SDRAM external device */
SDRAM_Initialization_Sequence(&hsdram, &command);
printf("Initiating SDRAM \r\n");
/*##-2- SDRAM memory read/write access #####################################*/
}
/**
* @brief Perform the SDRAM exernal memory inialization sequence
* @param hsdram: SDRAM handle
* @param Command: Pointer to SDRAM command structure
* @retval None
*/
static void SDRAM_Initialization_Sequence(SDRAM_HandleTypeDef *hsdram, FMC_SDRAM_CommandTypeDef *Command)
{
__IO uint32_t tmpmrd =0;
/* Step 1: Configure a clock configuration enable command */
Command->CommandMode = FMC_SDRAM_CMD_CLK_ENABLE;
Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2;;
Command->AutoRefreshNumber = 1;
Command->ModeRegisterDefinition = 0;
/* Send the command */
HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
/* Step 2: Insert 100 us minimum delay */
/* Inserted delay is equal to 1 ms due to systick time base unit (ms) */
HAL_Delay(1);
/* Step 3: Configure a PALL (precharge all) command */
Command->CommandMode = FMC_SDRAM_CMD_PALL;
Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2;
Command->AutoRefreshNumber = 1;
Command->ModeRegisterDefinition = 0;
/* Send the command */
HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
/* Step 4 : Configure a Auto-Refresh command */
Command->CommandMode = FMC_SDRAM_CMD_AUTOREFRESH_MODE;
Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2;
Command->AutoRefreshNumber = 8;
Command->ModeRegisterDefinition = 0;
/* Send the command */
HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
/* Step 5: Program the external memory mode register */
tmpmrd = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_1 |
SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL |
SDRAM_MODEREG_CAS_LATENCY_3 |
SDRAM_MODEREG_OPERATING_MODE_STANDARD |
SDRAM_MODEREG_WRITEBURST_MODE_SINGLE;
Command->CommandMode = FMC_SDRAM_CMD_LOAD_MODE;
Command->CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2;
Command->AutoRefreshNumber = 1;
Command->ModeRegisterDefinition = tmpmrd;
/* Send the command */
HAL_SDRAM_SendCommand(hsdram, Command, SDRAM_TIMEOUT);
/* Step 6: Set the refresh rate counter */
/* Set the device refresh rate */
HAL_SDRAM_ProgramRefreshRate(hsdram, REFRESH_COUNT);
}