[参考译文] TM4C123GH6PM：Tiva C UART 未接收数据

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1255454/tm4c123gh6pm-tiva-c-uart-not-receiving-data

我正在尝试使用 UART 将 Tiva C 与 FTDI 连接起来。 我能够从 Tiva 中发送数据并在 FTDI 中接收、但无法从 FTDI 中读取 Tiva 中的数据。 我正在使用以下配置：

115200bps、8个数据位、1个停止位、无奇偶校验

我的硬件连接有：

TX (FTDI)、带有 RX - PC4 (TIVA)
RX (FTDI)、带有 TX - PC5 (TIVA)

两者的接地引脚相互连接。

我已经使用 UART 通过 ESP32测试了 FTDI、它可以正常工作。 请帮助我解决此问题。 我有附加代码、以防软件配置错误。

#include <string.h>
#include "color_generator.h"
#include "inc/hw_ints.h"
#include "driverlib/uart.h"
#include "driverlib/interrupt.h"

#define MAX_SIZE 17
#define BAUD_RATE 115200
#define DELAY 50000000

char received_message[MAX_SIZE];
uint8_t loop_var = 0;
uint32_t len = 0;
const char* messages[] = {"WiFi started", "HTTP started", "WiFi connected"};
const char* text = "Received message: ";
const char* clear_screen = "\033[2J";
const char* newline_carriage_return = "\n\r";
const char* acknowledgement = "Indicating status...";

void uart_setup()
{
    // enable interrupts
    IntEnable(INT_UART4_TM4C123);

    // logging
    // enable gpio port A
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOA))
    {
        // wait till peripheral is ready
    }
    GPIOPinConfigure(GPIO_PA0_U0RX | GPIO_PA1_U0TX);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    // enable UART0
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_UART0))
    {
        // wait till peripheral is ready
    }
    UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), BAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE);
    UARTEnable(UART0_BASE);

    // communication with FTDI
    // enable gpio port C
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOC))
    {
        // wait till peripheral is ready
    }
    GPIOPinConfigure(GPIO_PC4_U4RX | GPIO_PC5_U4TX);
    GPIOPinTypeUART(GPIO_PORTC_BASE, GPIO_PIN_4 | GPIO_PIN_5);

    // enable UART4
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART4);
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_UART4))
    {
        // wait till peripheral is ready
    }
    UARTIntEnable(UART4_BASE, UART_INT_RT);
    // UARTLoopbackEnable(UART4_BASE);
    UARTConfigSetExpClk(UART4_BASE, SysCtlClockGet(), BAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE);
    UARTEnable(UART4_BASE);
}

void debug_led()
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    while (!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOF))
    {
        // wait till peripheral is ready
    }
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3);
    GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3, 0);
}

void uart_handler()
{
    UARTIntClear(UART4_BASE, UART_INT_RT);

    loop_var = 0;

    while (UARTCharsAvail(UART4_BASE) && loop_var < MAX_SIZE)
    {
        // GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, GPIO_PIN_1);
        int32_t ch = UARTCharGet(UART4_BASE);
        // log_to_uart(&ch);
        received_message[loop_var] = ch;
        loop_var++;
    }

    // write received text to console
    log_to_uart(newline_carriage_return);
    log_to_uart(text);
    // GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, GPIO_PIN_1);
    log_to_uart(received_message);

    write_to_uart(acknowledgement);
}

void write_to_uart(const char* text)
{
    len = strlen(text);
    for (loop_var = 0; loop_var < len; loop_var++)
    {
        UARTCharPut(UART4_BASE, text[loop_var]);
        while (UARTBusy(UART4_BASE))
        {
            // wait till transmit FIFO is empty
        }
    }
}

void log_to_uart(const char* text)
{
    len = strlen(text);
    for (loop_var = 0; loop_var < len; loop_var++)
    {
        UARTCharPut(UART0_BASE, text[loop_var]);
        while (UARTBusy(UART0_BASE))
        {
            // wait till transmit FIFO is empty
        }
    }
}

int main(int argc, char const *argv[])
{
    // set system clock frequency to 16 MHz
    SysCtlClockSet(SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

    // setup
    uart_setup();

    log_to_uart(clear_screen);
    
    debug_led();    // debug

    while (true)
    {
        // listen for input
        // write_to_uart("loopback");
        // SysCtlDelay(DELAY);
    }
       
    return 0;
}