Hello we try to use the backup sram on 0x3880 0000 .
We have build the software :
#define BKPSRAM_BASE 0x38800000UL
#define BKPSRAM_SIZE 0x1000UL
typedef enum
{
BkpSram_Init = 0 ,
BkpSram_Wait = 1 ,
BkpSram_WriteStr = 2 ,
BkpSram_ReadStr = 3 ,
BkpSram_Read8 = 4 ,
BkpSram_Write8 = 5 ,
BkpSram_Read16 = 6 ,
BkpSram_Write16 = 7 ,
BkpSram_Read32 = 8 ,
BkpSram_Write32 = 9 ,
BkpSram_Reset = 10 ,
}En_BackupSramCmd;
typedef struct
{
uint32_t counter;
float temperature;
char name[16];
} Bkp_StrTest;
Bkp_StrTest BkpStr_Test = { 42, 25.5f, "STM32H735" };
Bkp_StrTest BkpStr_Read = { 0};
typedef struct
{
En_BackupSramCmd Cmd;
Bkp_StrTest *StrTest;
Bkp_StrTest *StrRead;
}Str_BackupTest;
Str_BackupTest BackupTest;
void BackupSRAM_Test(void)
{
Str_BackupTest* this =&BackupTest;
switch(this->Cmd)
{
default:
HAL_PWR_EnableBkUpAccess();
HAL_PWREx_EnableBkUpReg();
while ((PWR->CR2 & PWR_CR2_BRRDY) == 0) {}
this->StrTest = &BkpStr_Test;
this->StrRead = &BkpStr_Read;
this->Cmd = BkpSram_Wait;
break;
case BkpSram_Wait:
break;
// ecrire une structure
case BkpSram_WriteStr:
this->Cmd = BkpSram_Wait;
BackupSRAM_WriteBuffer(0, this->StrTest, sizeof(Bkp_StrTest));
break;
// relire une structure
case BkpSram_ReadStr:
this->Cmd = BkpSram_Wait;
BackupSRAM_ReadBuffer(0, this->StrRead, sizeof(Bkp_StrTest));
break;
case BkpSram_Reset:
this->Cmd = BkpSram_Wait;
NVIC_SystemReset();
break;
}
}
The BackupSRAM_WriteBuffer and BackupSRAM_ReadBuffer is OK
but when we send the Cmd NVIC_SystemReset()and
read the backup register with BackupSRAM_ReadBuffer(...) the Read is all data at 0
--> this means that reset have kill my write
--> WHY ?
Edited to apply source code formatting - please see How to insert source code for future reference.
