diff options
Diffstat (limited to 'stm32-sdram.c')
| -rw-r--r-- | stm32-sdram.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/stm32-sdram.c b/stm32-sdram.c new file mode 100644 index 0000000..16386e8 --- /dev/null +++ b/stm32-sdram.c @@ -0,0 +1,106 @@ +//-----------------------------------------------------------------------------
+// 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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