FX3学习笔记4-pwm

1、实验环境

• 硬件平台：CYUSB3KIT-003 EZ-USB® FX3™ SuperSpeed Explorer Kit

• sdk版本：EZ-USB FX3 SDK1.3 / SuperSpeed Explorer Kit 1.0

• 实验例程：cyfxuvc_an75779（cypress官网下载demo）

2、实验目的

• 使用CYUSB3KIT-003的gpio_50(板子丝印I2S_CLK)输出pwm

3、程序添加

• 3.1 修改main函数gpio配置

  GPIOs 50, 51 and 52 are used as complex GPIO

/*GPIOs 50, 51 and 52 are used as complex GPIO*/
io_cfg.gpioComplexEn[0] = 0;
io_cfg.gpioComplexEn[1] = 0x001C0000;

• 3.2 添加pwm的gpio初始化函数

/* GPIO application initialization function. */
void
CyFxGpioInit (void)
{
    CyU3PGpioComplexConfig_t gpioConfig;
    CyU3PReturnStatus_t apiRetStatus = CY_U3P_SUCCESS;
    
    //一个工程只能初始化一次gpioClock，如果其它地方初始化了，这里要屏蔽
#if 0
    CyU3PGpioClock_t gpioClock;

    /* Init the GPIO module. The GPIO block will be running
     * with a fast clock at SYS_CLK / 2 and slow clock is not
     * used. For the DVK, the SYS_CLK is running at 403 MHz.*/
    gpioClock.fastClkDiv = 2;
    gpioClock.slowClkDiv = 0;
    gpioClock.simpleDiv = CY_U3P_GPIO_SIMPLE_DIV_BY_2;
    gpioClock.clkSrc = CY_U3P_SYS_CLK;
    gpioClock.halfDiv = 0;

   // apiRetStatus = CyU3PGpioInit(&gpioClock, NULL);
    if (apiRetStatus != 0)
    {
        /* Error Handling */
        CyU3PDebugPrint (4, "CyU3PGpioInit failed, error code = %d\n", apiRetStatus);
        CyFxAppErrorHandler(apiRetStatus);
    }
#endif
    /* Configure GPIO 50 as PWM output */
    gpioConfig.outValue = CyFalse;
    gpioConfig.inputEn = CyFalse;
    gpioConfig.driveLowEn = CyTrue;
    gpioConfig.driveHighEn = CyTrue;
    gpioConfig.pinMode = CY_U3P_GPIO_MODE_PWM;
    gpioConfig.intrMode = CY_U3P_GPIO_NO_INTR;
    gpioConfig.timerMode = CY_U3P_GPIO_TIMER_HIGH_FREQ;
    gpioConfig.timer = 0;
    gpioConfig.period = 10; //周期
    gpioConfig.threshold = 5; //占空比
    apiRetStatus = CyU3PGpioSetComplexConfig(50, &gpioConfig);
    if (apiRetStatus != CY_U3P_SUCCESS)
    {
        CyU3PDebugPrint (4, "CyU3PGpio50SetComplexConfig failed, error code = %d\n",
                apiRetStatus);
        CyFxAppErrorHandler(apiRetStatus);
    }

    /* Configure GPIO 51 as input for single time low measurement. */
    gpioConfig.outValue = CyTrue;
    gpioConfig.inputEn = CyTrue;
    gpioConfig.driveLowEn = CyFalse;
    gpioConfig.driveHighEn = CyFalse;
    /* For doing one time measurements, this value should be
     * set to static. For doing contiunous measurement, this
     * value should be set to the required mode. */
    gpioConfig.pinMode = CY_U3P_GPIO_MODE_STATIC;
    gpioConfig.intrMode = CY_U3P_GPIO_NO_INTR;
    gpioConfig.timerMode = CY_U3P_GPIO_TIMER_HIGH_FREQ;
    gpioConfig.timer = 0;
    /* Load the period to the maximum value
     * so that the count is not reset. */
    gpioConfig.period = 0xFFFFFFFF;
    gpioConfig.threshold = 0;
    apiRetStatus = CyU3PGpioSetComplexConfig(51, &gpioConfig);
    if (apiRetStatus != CY_U3P_SUCCESS)
    {
        CyU3PDebugPrint (4, "CyU3PGpio51SetComplexConfig failed, error code = %d\n",
                apiRetStatus);
        CyFxAppErrorHandler(apiRetStatus);
    }

    /* Enable a weak pullup on GPIO 52. */
    apiRetStatus = CyU3PGpioSetIoMode (52, CY_U3P_GPIO_IO_MODE_WPU);
    if (apiRetStatus != CY_U3P_SUCCESS)
    {
        CyU3PDebugPrint (4, "CyU3PGpioSetIoMode failed, error code = %d\n",
                apiRetStatus);
        CyFxAppErrorHandler(apiRetStatus);
    }

    /* Configure GPIO 52 as input for counter mode. */
    gpioConfig.outValue = CyTrue;
    gpioConfig.inputEn = CyTrue;
    gpioConfig.driveLowEn = CyFalse;
    gpioConfig.driveHighEn = CyFalse;
    gpioConfig.pinMode = CY_U3P_GPIO_MODE_STATIC;
    gpioConfig.intrMode = CY_U3P_GPIO_NO_INTR;
    gpioConfig.timerMode = CY_U3P_GPIO_TIMER_NEG_EDGE;
    gpioConfig.timer = 0;
    /* Load the period to the maximum value
     * so that the count is not reset. */
    gpioConfig.period = 0xFFFFFFFF;
    gpioConfig.threshold = 0;
    apiRetStatus = CyU3PGpioSetComplexConfig(52, &gpioConfig);
    if (apiRetStatus != CY_U3P_SUCCESS)
    {
        CyU3PDebugPrint (4, "CyU3PGpioSetComplexConfig failed, error code = %d\n",
                apiRetStatus);
        CyFxAppErrorHandler(apiRetStatus);
    }
}

 注意：一个工程只能初始化一次gpioClock，代码中屏蔽了初始化代码 ，因为其它地方已经初始化，根据实际情况决定要不要打开

• 3.3调用pwm初始化函数

void
UVCAppThread_Entry (
        uint32_t input)
{
    CyU3PReturnStatus_t apiRetStatus;
    uint32_t            flag;

    /* Initialize the Uart Debug Module */
    CyFxUVCApplnDebugInit ();

    /* Initialize the I2C interface */
    CyFxUVCApplnI2CInit ();

    /* Initialize the UVC Application */
    CyFxUVCApplnInit ();

    /*add by allen gpio 50 output pwm*/
    CyFxGpioInit();

ps:可以自己新建一个线程专门控制pwm，也可以在原有线程中添加，本例在官方原有线程中添加的。

• 3.4 pwm频率和占空比动态调整API

/** \brief Update the timer period and threshold associated with a complex GPIO.

    **Description**\n
    The function updates the timer period and threshold value associated with a
    complex GPIO. This operation is only permitted if the corresponding is configured
    in the PWM or STATIC modes.

    **Return value**\n
    * CY_U3P_SUCCESS              - If the operation is successful.\n
    * CY_U3P_ERROR_NOT_STARTED    - If the GPIO block has not been initialized.\n
   * CY_U3P_ERROR_BAD_ARGUMENT   - If the IO pin is invalid.

    **\see
    *\see CyU3PGpioSetComplexConfig
    *\see CyU3PGpioComplexGetThreshold
 */
extern CyU3PReturnStatus_t
CyU3PGpioComplexUpdate (
        uint8_t gpioId,                 /**< The complex GPIO to sample. */
        uint32_t threshold,             /**< New timer threshold value to be updated. */
        uint32_t period                 /**< New timer period value to be updated. */
        );

4 测试

• 使用示波器可以看到pwm输出