[参考译文] AM2634：DMA 模式下的 UART 接收中断

尊敬的 Rohal：

您能否解释一下在这里为 UART_read API 使用 while 循环时"持续"的含义？

此致、

Anil

连续意味着在获得8个字节(阈值设置值)后、它应该准备好接收接下来的8个字节、依此类推、因为现有示例代码仅在我需要它一定程度时有效一次。

请告诉我如何 在 UART 上接收可变长度数据、因为根据我的应用、用户可以发送 可变大小的数据、这意味着有时他可以发送10、20或50个字节   

尊敬的 Rohal：

yutong 说：

连续意味着在获得8字节(阈值设定值)后、它应该准备好接收下一个8字节、依此类推、因为现有示例代码仅在我有限需要时运行一次。

目前、该应用旨在从用户获取8B 输入、然后回显相同的8B 并退出应用、因此您必须修改该应用、以保持接收数据(例如在 while 循环中、继续接收数据)。

此致、
Shaunak

我也尝试了该功能、但它在获得8个字节后未接收到任何中断、因此我们是否需要清除所有中断标志以使其再次运行

 CacheP_WBInv ((void *)&gUartReceiveBuffer[0U]、APP_UART_RECEIVE_BUFSIZE、CacheP_TYPE_ALL)；  

上述 API 阻止了我的过程、请告诉我如何删除高速缓存、并在每次接收字节时获取中断  

我们是否可以使用 具有中断平均值的 DMA 在发送所有数据后执行传输 Get 中断、在获取数据后执行接收 Get 中断(仅 DMA 执行所有传输和接收)  

是的、请尽快查看此内容、

这里还注意到一个问题、

我在 DMA 模式下配置5字节接收中断、它仅在5个字节内正常工作、如果用户发送的字节超过5、则让6停止接收中断、  

我将共享该代码、也请检查

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 */

/* This example demonstrates the UART RX and TX operation by echoing char
 * that it recieves in blocking, interrupt mode of operation.
 * When user types 'quit', the application ends.
 */

#include <string.h>
#include <kernel/dpl/DebugP.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"


#define APP_UART_BUFSIZE              (200U)
#define APP_UART_RECEIVE_BUFSIZE      (20U)

uint8_t gUartBuffer[APP_UART_BUFSIZE] __attribute__((aligned(CacheP_CACHELINE_ALIGNMENT)));
uint8_t gUartReceiveBuffer[APP_UART_RECEIVE_BUFSIZE] __attribute__((aligned(CacheP_CACHELINE_ALIGNMENT)));
volatile uint32_t gNumBytesRead = 0U, gNumBytesWritten = 0U;

#define APP_UART_ASSERT_ON_FAILURE(transferOK, transaction) \
    do { \
        if((SystemP_SUCCESS != (transferOK)) || (UART_TRANSFER_STATUS_SUCCESS != transaction.status)) \
        { \
            DebugP_assert(FALSE); /* UART TX/RX failed!! */ \
        } \
    } while(0) \


static SemaphoreP_Object gUartWriteDoneSem;
static SemaphoreP_Object gUartReadDoneSem;
static uint8_t rxcomplete=0;
void uart_echo_dma(void *args)
{
    int32_t          transferOK, status;
    UART_Transaction trans;
    UART_Transaction transRx;

    Drivers_open();
    Board_driversOpen();

    DebugP_log("[UART] Echo example DMA mode started ...\r\n");

    status = SemaphoreP_constructBinary(&gUartWriteDoneSem, 0);
    DebugP_assert(SystemP_SUCCESS == status);

    status = SemaphoreP_constructBinary(&gUartReadDoneSem, 0);
    DebugP_assert(SystemP_SUCCESS == status);
    UART_Transaction_init(&trans);
    UART_Transaction_init(&transRx);

    /* Send entry string */
    gNumBytesWritten = 0U;
    trans.buf   = &gUartBuffer[0U];
    strncpy(trans.buf,"This is uart echo test DMA blocking mode\r\nReceives 8 characters then echo's back. Please input..\r\n", APP_UART_BUFSIZE);
    trans.count = strlen(trans.buf);
    CacheP_wb((void *)trans.buf, trans.count, CacheP_TYPE_ALL);
    transferOK = UART_write(gUartHandle[CONFIG_UART_CONSOLE], &trans);

    APP_UART_ASSERT_ON_FAILURE(transferOK, trans);
    SemaphoreP_pend(&gUartWriteDoneSem, SystemP_NO_WAIT);

    CacheP_wbInv((void *)&gUartReceiveBuffer[0U], APP_UART_RECEIVE_BUFSIZE, CacheP_TYPE_ALL);
    /* Read 8 chars */
    gNumBytesRead = 0U;
    transRx.buf   = &gUartReceiveBuffer[0U];
    transRx.count = 5;
    transferOK = UART_read(gUartHandle[CONFIG_UART_CONSOLE], &transRx);
    APP_UART_ASSERT_ON_FAILURE(transferOK, transRx);
    SemaphoreP_pend(&gUartReadDoneSem, SystemP_NO_WAIT);

    /* Echo chars entered */

    while(1)
    {
        if(rxcomplete==1)
        {
            gNumBytesWritten = 0U;
            trans.buf   = &gUartReceiveBuffer[0U];
            trans.count = transRx.count;
            transferOK = UART_write(gUartHandle[CONFIG_UART_CONSOLE], &trans);
            APP_UART_ASSERT_ON_FAILURE(transferOK, trans);
            SemaphoreP_pend(&gUartWriteDoneSem, SystemP_NO_WAIT);
            rxcomplete=0;

            gNumBytesRead = 0U;
            transRx.buf   = &gUartReceiveBuffer[0U];
            transRx.count = 5;
            transferOK = UART_read(gUartHandle[CONFIG_UART_CONSOLE], &transRx);
            APP_UART_ASSERT_ON_FAILURE(transferOK, transRx);
            SemaphoreP_pend(&gUartReadDoneSem, SystemP_NO_WAIT);
        }
    }
    /* Send exit string */

    return;
}
void RxCallback(UART_Handle handle, UART_Transaction *transaction)
{
    DebugP_assertNoLog(UART_TRANSFER_STATUS_SUCCESS == transaction->status);
    gNumBytesRead = transaction->count;
    SemaphoreP_post(&gUartReadDoneSem);
    rxcomplete=1;
//        (void)RTI_counterEnable(CONFIG_RTI0_BASE_ADDR, RTI_TMR_CNT_BLK_INDEX_0);


}

void TxCallBack(UART_Handle handle, UART_Transaction *transaction)
{
    DebugP_assertNoLog(UART_TRANSFER_STATUS_SUCCESS == transaction->status);
       gNumBytesWritten = transaction->count;
       SemaphoreP_post(&gUartWriteDoneSem);
}
uint8_t timer1ms;
void TimerCallback()
{
    timer1ms++;
//    rxcomplete = 1;
    (void)RTI_counterDisable(CONFIG_RTI0_BASE_ADDR, RTI_TMR_CNT_BLK_INDEX_0);

}

请建议还如何处理 UART 错误(帧错误和过度运行错误)