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//-----------------------------------------------------------------------------
// stm32-sdram.c
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// Headers
//-----------------------------------------------------------------------------
#include "stm32f4xx_hal.h"
#include "stm32-sdram.h"
//-----------------------------------------------------------------------------
int sdram_init(SDRAM_HandleTypeDef *sdram1, SDRAM_HandleTypeDef *sdram2)
//-----------------------------------------------------------------------------
{
HAL_StatusTypeDef ok; // status
FMC_SDRAM_CommandTypeDef cmd; // command
//
// enable clocking
//
cmd.CommandMode = FMC_SDRAM_CMD_CLK_ENABLE;
cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;
cmd.AutoRefreshNumber = 1;
cmd.ModeRegisterDefinition = 0;
HAL_Delay(1);
ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);
if (ok != HAL_OK) return 0;
//
// precharge all banks
//
cmd.CommandMode = FMC_SDRAM_CMD_PALL;
cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;
cmd.AutoRefreshNumber = 1;
cmd.ModeRegisterDefinition = 0;
HAL_Delay(1);
ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);
if (ok != HAL_OK) return 0;
//
// send two auto-refresh commands in a row
//
cmd.CommandMode = FMC_SDRAM_CMD_AUTOREFRESH_MODE;
cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;
cmd.AutoRefreshNumber = 1;
cmd.ModeRegisterDefinition = 0;
ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);
if (ok != HAL_OK) return 1;
ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);
if (ok != HAL_OK) return 1;
//
// load mode register
//
cmd.CommandMode = FMC_SDRAM_CMD_LOAD_MODE;
cmd.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK1_2;
cmd.AutoRefreshNumber = 1;
cmd.ModeRegisterDefinition = SDRAM_MODEREG_BURST_LENGTH_1 |
SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL |
SDRAM_MODEREG_CAS_LATENCY_2 |
SDRAM_MODEREG_OPERATING_MODE_STANDARD |
SDRAM_MODEREG_WRITEBURST_MODE_SINGLE ;
ok = HAL_SDRAM_SendCommand(sdram1, &cmd, 1);
if (ok != HAL_OK) return 1;
//
// set number of consequtive auto-refresh commands
// and program refresh rate
//
//
// RefreshRate = 64 ms / 8192 cyc = 7.8125 us/cyc
//
// RefreshCycles = 7.8125 us * 90 MHz = 703
//
// According to the formula on p.1665 of the reference manual,
// we also need to subtract 20 from the value, so the target
// refresh rate is 703 - 20 = 683.
//
ok = HAL_SDRAM_SetAutoRefreshNumber(sdram1, 8);
if (ok != HAL_OK) return 1;
HAL_SDRAM_ProgramRefreshRate(sdram1, 683);
if (ok != HAL_OK) return 1;
// done
return 1;
}
//-----------------------------------------------------------------------------
// End-of-File
//-----------------------------------------------------------------------------
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