MSP432E401Y: MSP-EXP432E401Y,Development Kit,TI LanchPad.向上计数模式不能自己设置什么时候进行重新填充。

han chen

Part Number: MSP432E401Y

1.我已经看过https://dev.ti.com/tirex/explore/node?node=AOD4LXqFA8XEr21FehvtQA__J4.hfJy__LATEST和dev.ti.com/.../node，为了不耽误您的工作请不要重新发送

2.我已经看过这本参考手册，并且从中找到相关的描述，为了不耽误您的工作请不要重新发送

3.向下计数模式可以设置为10000数到0，这是没有问题的

4.我的代码如下所示，我仅仅将97行的TIMER_CFG_B_PERIODIC，改为TIMER_CFG_B_PERIODIC _UP，将105行的数据改为10000方便观察LED的闪烁频率。

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/******************************************************************************
 * MSP432E4 Example project for Configuring a timer in 16-bit periodic mode
 *
 * Description: In this example, the timer is configured to generate an
 * interrupt every 0.1 sec in 16-bit periodic mode. On the interrupt the state
 * of the LED D2
 *
 *                MSP432E401Y
 *             ------------------
 *         /|\|                  |
 *          | |                  |
 *          --|RST               |
 *            |                  |
 *            |               PN0|-->LED
 *            |                  |
 *            |                  |
 *            |                  |
 * Author: Amit Ashara
*******************************************************************************/
/* DriverLib Includes */
#include <ti/devices/msp432e4/driverlib/driverlib.h>

/* Standard Includes */
#include <stdint.h>
#include <stdbool.h>

void TIMER2B_IRQHandler(void)
{
    uint32_t getTimerInterrupt;

    /* Get timer interrupt status  and clear the same */
    getTimerInterrupt = MAP_TimerIntStatus(TIMER2_BASE, true);
    MAP_TimerIntClear(TIMER2_BASE, getTimerInterrupt);

    /* Toggle the LED */
    MAP_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0,
                     ~(MAP_GPIOPinRead(GPIO_PORTN_BASE, GPIO_PIN_0)));
}

int main(void)
{
    uint32_t systemClock;

    /* Configure the system clock for 120 MHz */
    systemClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN |
                                          SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480),
                                          120000000);

    /* Enable the clock to the GPIO Port N and wait for it to be ready */
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPION);
    while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_GPION)))
    {
    }

    /* Configure the GPIO PN0 as output and put in low state */
    MAP_GPIOPinTypeGPIOOutput(GPIO_PORTN_BASE, GPIO_PIN_0);
    MAP_GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, ~(GPIO_PIN_0));

    /* Enable the Timer-0 in 16-bit periodic mode with interrupt generated
     * every 0.1 sec */
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER2);
    while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_TIMER2)))
    {
    }

    MAP_TimerConfigure(TIMER2_BASE, TIMER_CFG_SPLIT_PAIR | TIMER_CFG_B_PERIODIC_UP);
    MAP_TimerIntEnable(TIMER2_BASE, TIMER_TIMB_TIMEOUT);

    /* Since the 16-bit timer can count only 65536 value, we use the pre
     * scaler of 256 to divide down the count rate by 256. Thus the actual
     * count load is 120e6/256 = 468750. Now when to count at 0.1 sec the
     * load value in the timer would be 468750 * 0.1 = 46875 = 0xB71B. */
    MAP_TimerPrescaleSet(TIMER2_BASE, TIMER_B, 255);
    MAP_TimerLoadSet(TIMER2_BASE, TIMER_B, 10000);

    /* Enable Timer Interrupt */
    MAP_IntEnable(INT_TIMER2B);

    /* Enable the timer count */
    MAP_TimerEnable(TIMER2_BASE, TIMER_B);

    while(1)
    {
    }
}

5.（4.）中提到过的代码在运行时可以看到，97行参数为TIMER_CFG_B_PERIODIC时，灯会极速闪烁，TIMER_CFG_B_PERIODIC _UP时则并不会。实际上我在工作时已经检查到，这并不是0-10000的向上或者向下计数，而是0-65535，已经得到确认，您大可放心。

6.（5.）中的错误在去掉104行不进行分频的时候并不会出现

7. 感谢TI的工程师的耐心，请您尝试和观察，帮帮一个迷茫的人

2 年多前