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Help me about a delay in MCU startup

hamed ad

Hi
I have made a header board for STM32L152VD after every restart it takes few seconds for the board to start running. I use HSI clock. what do you think the problem is?

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  • 0 in reply to Westonsupermare Pier

    -> after power on, the LED starts flashing rapidly for few seconds (between 2 to 10 seconds) then LED becomes steadily on.

    I encountered similar problem before.

    The LCD of our device shares the same pins with a FT240X USB Chip, our device has a Lithium battery and a USB charging circuit. I encountered similar problem as you, so I discuss this problem with my hardware colleague, he did a full hardware analysis, and told me that this hardware needs a few seconds to become stable after power on. Since hardware can't be modified, he asked me to do a Sleep_Mode_IO_Config() immediately after power on, then wait for a while, then start to do the Runtime_IO_Config() and the real work. After this software modification, the problem doesn't disappear, but under our control.

    Sleep_Mode_IO_Config(): He checked and decided each GPIO pins should be configured as In or Out, if it is an output pin, it should be high or low.

    int main(void)
{
    int i;
    static uint8_t Wait_PC_Connect = 1;

    LPC_SYSCON->PDRUNCFG |= (1u<<3);    /* Set BOD Power-Down bit */
    GPIO_OutInit();
    Enable_Timer32B0();

    Sleep_Mode_IO_Config();
    delay_in_ms(50);
    GPIOSetValue( LPC_GPIO0, 7, 1 );    // En_OP_Power - ON
    Blink_Delay(8);
    Runtime_IO_Config();

    ADC_Init();
    SSP_Init();
    I2C_Init( LPC_I2C, 400000 );
    UART_Init(115200);

    delay_in_ms(10);
    LCD_Init();
    delay_in_ms(10);
    GPIOSetValue( LPC_GPIO2, 10, 1 );    // LCD_BKL - ON

Reply
  • 0 in reply to Westonsupermare Pier

    -> after power on, the LED starts flashing rapidly for few seconds (between 2 to 10 seconds) then LED becomes steadily on.

    I encountered similar problem before.

    The LCD of our device shares the same pins with a FT240X USB Chip, our device has a Lithium battery and a USB charging circuit. I encountered similar problem as you, so I discuss this problem with my hardware colleague, he did a full hardware analysis, and told me that this hardware needs a few seconds to become stable after power on. Since hardware can't be modified, he asked me to do a Sleep_Mode_IO_Config() immediately after power on, then wait for a while, then start to do the Runtime_IO_Config() and the real work. After this software modification, the problem doesn't disappear, but under our control.

    Sleep_Mode_IO_Config(): He checked and decided each GPIO pins should be configured as In or Out, if it is an output pin, it should be high or low.

    int main(void)
{
    int i;
    static uint8_t Wait_PC_Connect = 1;

    LPC_SYSCON->PDRUNCFG |= (1u<<3);    /* Set BOD Power-Down bit */
    GPIO_OutInit();
    Enable_Timer32B0();

    Sleep_Mode_IO_Config();
    delay_in_ms(50);
    GPIOSetValue( LPC_GPIO0, 7, 1 );    // En_OP_Power - ON
    Blink_Delay(8);
    Runtime_IO_Config();

    ADC_Init();
    SSP_Init();
    I2C_Init( LPC_I2C, 400000 );
    UART_Init(115200);

    delay_in_ms(10);
    LCD_Init();
    delay_in_ms(10);
    GPIOSetValue( LPC_GPIO2, 10, 1 );    // LCD_BKL - ON

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