How To Using FMC Write?

[Dlak]

I encountered a problem when trying to send more than 5 bytes of data using the FMC.

// impossible example --

#define SD_DATA       (*(volatile unsigned char *)0x60000001)

SD_DATA = 0x01;
SD_DATA = 0x02;
SD_DATA = 0x03;

Using this method, data is not transmitted to the same address without a delay.

However, it is possible to write data to the FMC if I change the address each time I transmit or use a delay.

// possible example -- 1

#define SD_DATA       (*(volatile unsigned char *)0x60000001)

SD_DATA = 0x01;
HAL_Delay(1);
SD_DATA = 0x02;
HAL_Delay(1);
SD_DATA = 0x03;

// possible example -- 2

#define SD_DATA1      (*(volatile unsigned char *)0x60000001)
#define SD_DATA2       (*(volatile unsigned char *)0x60000002)
#define SD_DATA3       (*(volatile unsigned char *)0x60000003)
SD_DATA1 = 0x01;
SD_DATA2 = 0x02;
SD_DATA3 = 0x03;

What could be the problem?

We used the STM32F756, and the following is the FMC initialization.

static void MX_FMC_Init(void)
{
  FMC_NORSRAM_TimingTypeDef Timing;


  /** Perform the NOR1 memory initialization sequence
  */
  hnor1.Instance = FMC_NORSRAM_DEVICE;
  hnor1.Extended = FMC_NORSRAM_EXTENDED_DEVICE;
  /* hnor1.Init */
  hnor1.Init.NSBank = FMC_NORSRAM_BANK1;
  hnor1.Init.DataAddressMux = FMC_DATA_ADDRESS_MUX_DISABLE;
  hnor1.Init.MemoryType = FMC_MEMORY_TYPE_NOR;
  hnor1.Init.MemoryDataWidth = FMC_NORSRAM_MEM_BUS_WIDTH_8;
  hnor1.Init.BurstAccessMode = FMC_BURST_ACCESS_MODE_DISABLE;
  hnor1.Init.WaitSignalPolarity = FMC_WAIT_SIGNAL_POLARITY_LOW;
  hnor1.Init.WaitSignalActive = FMC_WAIT_TIMING_BEFORE_WS;
  hnor1.Init.WriteOperation = FMC_WRITE_OPERATION_ENABLE;
  hnor1.Init.WaitSignal = FMC_WAIT_SIGNAL_DISABLE;
  hnor1.Init.ExtendedMode = FMC_EXTENDED_MODE_DISABLE;
  hnor1.Init.AsynchronousWait = FMC_ASYNCHRONOUS_WAIT_DISABLE;
  hnor1.Init.WriteBurst = FMC_WRITE_BURST_DISABLE;
  hnor1.Init.ContinuousClock = FMC_CONTINUOUS_CLOCK_SYNC_ONLY;
  hnor1.Init.WriteFifo = FMC_WRITE_FIFO_ENABLE;
  hnor1.Init.PageSize = FMC_PAGE_SIZE_NONE;

/* Timing */
  Timing.AddressSetupTime = 15;
  Timing.AddressHoldTime = 15;
  Timing.DataSetupTime = 31;
  Timing.BusTurnAroundDuration = 8;
  Timing.CLKDivision = 16;
  Timing.DataLatency = 17;
  Timing.AccessMode = FMC_ACCESS_MODE_A;
  /* ExtTiming */

  if (HAL_NOR_Init(&hnor1, &Timing, NULL) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }
}

[waclawek.jan]

> I have noticed that using BANK1 in FMC_Init causes a hard fault at addresses starting from 0x6000.0000.

After remap, you should not use 0x6000'0000 anymore.

JW

[Dlak]

I used 0x6000.0000 before remapping, but if BANK2 is not used during the initialization process, a hard fault occurs. What could be the problem?

[waclawek.jan]

At this point, I am already lost in what exactly do you do.

Please give us a short summary, what is your actual hardware, what are the FMC settings, and upon which action does the fault occur.

JW

[Dlak · Accepted solution]

Due to repeated swap errors, I resolved the issue by clearing the cache.