[参考译文] MSPM0G3507：UART 中断无法以特定的概率（大约为 1/10 的概率）启动

简短答案：在 DL_init 函数中、在 NVIC_ClearPendingIRQ 调用之前的某个时间、插入类似的内容：

>(void) DL_UART_Main_receiveData (UART_2_INST)；//读取并丢弃（和清除状态）

更长的答案：我可以通过清除 UART IRQ（待处理时）来生成您的症状。 外设 (MIS) 指示了 Rx 中断、但 NVIC 不知道它、随后由于已设置 RIS 位、UART 没有向 NVIC 发出新的 IRQ（也称为“卡住“）。

TRM (SLAU846C) 第 3.3.1.1 节（“设置和清除挂起中断状态“小节）描述了外设 IRQ 的“级别“行为、但至少在这种情况下 (UART RX)、结果似乎与“脉冲“行为一致、一旦清除挂起状态、就不会重新发出该结果。

如果在调用 DL_init 时收到了一个字节、并且在 ClearPendingIRQ 之前完成了一段时间、则可能会遇到这种情况。 （浮点算术可能会扩展此处的窗口。）

常见的权变措施是在启用 RX 中断位 (RIS) 之前显式清除该位。 但我观察到、当接收器继续运行时、仍然不会发出 RX 中断（结果：RXDATA 以静默方式溢出）。 这大概是因为尚未读取 RXDATA。

最后清除内容的步骤是读取 RXDATA 寄存器（在本例中，我使用 OVRERR 来执行此操作）。 这也具有清除 RX 中断位的效果。 我建议您在启用中断时随意操作。

此测试程序可以在其挂起（在 NVIC 中）时每清除第 4 个 RX 中断。 输入终端仿真器时、每第 4 个/第 5 个字节不会回显、第一个字节是因为 IRQ 被清除、第二个字节是由于 OVRERR。 但 OVRERR 代码会清除条件、然后恢复正常。

c 文件：

/*
 * This started life as the uart_echo_interrupts_standby example
 */
#include "ti_msp_dl_config.h"
volatile uint32_t ctr;
volatile uint8_t gEchoData = 0;
int main(void)
{
    SYSCFG_DL_init();
    DL_UART_Main_enableInterrupt(UART_0_INST,
                              DL_UART_MAIN_INTERRUPT_OVERRUN_ERROR |
                                 DL_UART_MAIN_INTERRUPT_RX);

    NVIC_ClearPendingIRQ(UART_0_INST_INT_IRQN);
    NVIC_EnableIRQ(UART_0_INST_INT_IRQN);
    
    while (1) {
        __disable_irq(); // hold it off
        __WFI();
        asm volatile(" nop ");   // Breakpoint here
        ++ctr;
        if ((ctr & 0x03) == 0)
        {
            // Every 4th byte:
            DL_UART_clearInterruptStatus(UART_0_INST, DL_UART_INTERRUPT_RX );
            NVIC_ClearPendingIRQ(UART_0_INST_INT_IRQN);
        }
        __enable_irq(); // let it run
        asm volatile(" nop ");   // Keep the compiler from unrolling
    }
}

void UART_0_INST_IRQHandler(void)
{
    asm volatile(" nop "); // breakpoint here
    switch (DL_UART_Main_getPendingInterrupt(UART_0_INST)) {
        case DL_UART_MAIN_IIDX_RX:
            DL_GPIO_togglePins(GPIO_LEDS_PORT,
                GPIO_LEDS_USER_LED_1_PIN | GPIO_LEDS_USER_TEST_PIN);
            gEchoData = DL_UART_Main_receiveData(UART_0_INST);
            DL_UART_Main_transmitData(UART_0_INST, gEchoData);
            //DL_UART_clearInterruptStatus(UART_0_INST, DL_UART_INTERRUPT_RX );
            break;
        case DL_UART_IIDX_OVERRUN_ERROR:
            gEchoData = DL_UART_Main_receiveData(UART_0_INST);
            break;
        default:
            break;
    }
}

.syscfg：

/**
 * These arguments were used when this file was generated. They will be automatically applied on subsequent loads
 * via the GUI or CLI. Run CLI with '--help' for additional information on how to override these arguments.
 * @cliArgs --device "MSPM0G350X" --part "Default" --package "LQFP-64(PM)" --product "mspm0_sdk@2.07.00.06"
 * @v2CliArgs --device "MSPM0G3507" --package "LQFP-64(PM)" --product "mspm0_sdk@2.07.00.06"
 * @versions {"tool":"1.25.0+4268"}
 */

/**
 * Import the modules used in this configuration.
 */
const GPIO   = scripting.addModule("/ti/driverlib/GPIO", {}, false);
const GPIO1  = GPIO.addInstance();
const SYSCTL = scripting.addModule("/ti/driverlib/SYSCTL");
const UART   = scripting.addModule("/ti/driverlib/UART", {}, false);
const UART1  = UART.addInstance();

/**
 * Write custom configuration values to the imported modules.
 */
GPIO1.$name                          = "GPIO_LEDS";
GPIO1.associatedPins.create(2);
GPIO1.associatedPins[0].$name        = "USER_LED_1";
GPIO1.associatedPins[0].assignedPort = "PORTA";
GPIO1.associatedPins[0].initialValue = "SET";
GPIO1.associatedPins[0].assignedPin  = "0";
GPIO1.associatedPins[0].pin.$assign  = "PA0";
GPIO1.associatedPins[1].$name        = "USER_TEST";
GPIO1.associatedPins[1].assignedPort = "PORTA";
GPIO1.associatedPins[1].assignedPin  = "15";
GPIO1.associatedPins[1].initialValue = "SET";

const Board           = scripting.addModule("/ti/driverlib/Board", {}, false);
Board.configureUnused = true;

SYSCTL.forceDefaultClkConfig = true;
SYSCTL.clockTreeEn           = true;

UART1.$name                    = "UART_0";
UART1.rxFifoThreshold          = "DL_UART_RX_FIFO_LEVEL_ONE_ENTRY";
UART1.enableDMARX              = false;
UART1.enableDMATX              = false;
UART1.targetBaudRate           = 115200;
UART1.enabledInterrupts        = ["OVERRUN_ERROR","RX"];
UART1.peripheral.$assign       = "UART0";
UART1.peripheral.rxPin.$assign = "PA11";
UART1.peripheral.txPin.$assign = "PA10";
UART1.txPinConfig.$name        = "ti_driverlib_gpio_GPIOPinGeneric0";
UART1.rxPinConfig.$name        = "ti_driverlib_gpio_GPIOPinGeneric1";

/**
 * Pinmux solution for unlocked pins/peripherals. This ensures that minor changes to the automatic solver in a future
 * version of the tool will not impact the pinmux you originally saw.  These lines can be completely deleted in order to
 * re-solve from scratch.
 */
GPIO1.associatedPins[1].pin.$suggestSolution = "PA15";
Board.peripheral.$suggestSolution            = "DEBUGSS";
Board.peripheral.swclkPin.$suggestSolution   = "PA20";
Board.peripheral.swdioPin.$suggestSolution   = "PA19";