freemodbus 超时错误

发布于 2020-05-13 14:01:36 浏览：2669 订阅该版

9 个回答

断崖独坐 2020-05-13

这家伙很懒，什么也没写！

[i=s] 本帖最后由 断崖独坐 于 2020-5-13 15:23 编辑 [/i]

补充：用19200波特率测试，不会出现偶尔的不应答，也没有出现过超时
下边是freemodbus的定时器代码：

/* If baudrate > 19200 then we should use the fixed timer values
         * t35 = 1750us. Otherwise t35 must be 3.5 times the character time.
         */
        if( ulBaudRate > 19200 )
        {
            usTimerT35_50us = 35;       /* 1800us. */
        }
        else
        {
            /* The timer reload value for a character is given by:
             *
             * ChTimeValue = Ticks_per_1s / ( Baudrate / 11 )
             *             = 11 * Ticks_per_1s / Baudrate
             *             = 220000 / Baudrate
             * The reload for t3.5 is 1.5 times this value and similary
             * for t3.5.
             */
            usTimerT35_50us = ( 7UL * 220000UL ) / ( 2UL * ulBaudRate );
        }
        if( xMBPortTimersInit( ( USHORT ) usTimerT35_50us ) != TRUE )
        {
            eStatus = MB_EPORTERR;
        }
/* ----------------------- Start implementation -----------------------------*/
BOOL xMBPortTimersInit(USHORT usTim1Timerout50us)
{
    rt_timer_init(&timer, "slave timer",
                   timer_timeout_ind, /* bind timeout callback function */
                   RT_NULL,
                   (50 * usTim1Timerout50us) / (1000 * 1000 / RT_TICK_PER_SECOND) + 1,
                   RT_TIMER_FLAG_ONE_SHOT); /* one shot */
    return TRUE;
}