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 0CyU3PGpioClock_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**\nThe function updates the timer period and threshold value associated with acomplex GPIO. This operation is only permitted if the corresponding is configuredin 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

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