In our circuit diagram, PIN0_2 and PIN0_3 are used as serial ports. PIN0_2 and PIN0_3 are configured as USART3.But can not output messages.What should I pay attention to when configuring as usart3.Thanks.
 
					
				
		
 xiangjun_rong
		
			xiangjun_rong
		
		
		
		
		
		
		
		
	
			
		
		
			
					
		Hi,
I think you can refer to the following code to configure the pin as uart3:
#define IOCON_PIO_DIGITAL_EN 0x0100u  /*!<@brief Enables digital function */
#define IOCON_PIO_FUNC1 0x01u         /*!<@brief Selects pin function 1 */
#define IOCON_PIO_INPFILT_OFF 0x0200u /*!<@brief Input filter disabled */
#define IOCON_PIO_INV_DI 0x00u        /*!<@brief Input function is not inverted */
#define IOCON_PIO_MODE_INACT 0x00u    /*!<@brief No addition pin function */
#define IOCON_PIO_MODE_PULLUP 0x20u   /*!<@brief Selects pull-up function */
#define IOCON_PIO_OPENDRAIN_DI 0x00u  /*!<@brief Open drain is disabled */
#define IOCON_PIO_SLEW_STANDARD 0x00u /*!<@brief Standard mode, output slew rate control is enabled */
void uart3PinAssignment(void)
{
     uint32_t pin_config;
    //PINs Configuration for Master
      CLOCK_EnableClock(kCLOCK_Iocon);
      CLOCK_EnableClock(kCLOCK_Gpio0);
     // P0_2/FC3_TXD, 
    pin_config = (/* Pin is configured as FC3_TXD */
                                         IOCON_PIO_FUNC1 |
                                         /* Selects pull-up function */
                                         IOCON_PIO_MODE_PULLUP |
                                         /* Input function is not inverted */
                                         IOCON_PIO_INV_DI |
                                         /* Enables digital function */
                                         IOCON_PIO_DIGITAL_EN |
                                         /* Input filter disabled */
                                         IOCON_PIO_INPFILT_OFF |
                                         /* Standard mode, output slew rate control is enabled */
                                         IOCON_PIO_SLEW_STANDARD |
                                         /* Open drain is disabled */
                                         IOCON_PIO_OPENDRAIN_DI);
IOCON_PinMuxSet(IOCON, 0, 2, pin_config);
    // P0_3/FC3_RXD, 
    pin_config = (/* Pin is configured as FC3_RXD */
                                           IOCON_PIO_FUNC1 |
                                           /* Selects pull-up function */
                                           IOCON_PIO_MODE_PULLUP |
                                           /* Input function is not inverted */
                                           IOCON_PIO_INV_DI |
                                           /* Enables digital function */
                                           IOCON_PIO_DIGITAL_EN |
                                           /* Input filter disabled */
                                           IOCON_PIO_INPFILT_OFF |
                                           /* Standard mode, output slew rate control is enabled */
                                           IOCON_PIO_SLEW_STANDARD |
                                           /* Open drain is disabled */
                                           IOCON_PIO_OPENDRAIN_DI);
      
     IOCON_PinMuxSet(IOCON, 0, 3, pin_config);
    //Reset FC3
    SYSCON->PRESETCTRL[1]|=1<<14;
    SYSCON->PRESETCTRL[1]&=~(1<<14);
    //set gated clock of FC3
    SYSCON->AHBCLKCTRL[1]|=1<<14;
    //set the FC3 as spi
    FLEXCOMM3->PSELID=0x01;
    //set uart3 clock divider
    //select 12MHz FRO_12M
    SYSCON->FCLKSEL[3]=0x00;
}
Hope it can help you
BR
XiangJun Rong
Hi XiangJun Rong:
Thanks!
BR
Aifei Zhang
发件人: xiangjun.rong
发送时间: 2019年12月9日 14:01
收件人: Aifei Zhang
主题: Re: - Re: LPC54016JET100 USART3 OUTPUT PROBLEM
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Re: LPC54016JET100 USART3 OUTPUT PROBLEM
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