Timeout

This sample uses ENHTIM to generate a timeout interrupt every second.

To facilitate observation, connect the P0_0 pin to LED0 on the EVB board.

When the timer reaches 1 second, an interrupt will be triggered. In the interrupt handler function, the program will toggle the level of the P0_0 pin, changing the output polarity of the GPIO, thereby making LED0 blink once every second.

Enhance-Timer timeout diagram

Users can modify pin information, timing, and more through different macro configurations. For detailed macro configurations, refer to Configurations.

Requirements

For requirements, please refer to the Requirements.

Wiring

Connect P0_0 to LED0 on the EVB.

The LED driver circuit is shown below.

LED Driver Circuit Diagram

Configurations

1. The following macro can be configured to modify the pin definition.

   #define OUTPUT_PIN          P0_0
   #define GPIO_PIN            GPIO_GetPin(OUTPUT_PIN)
   #define GPIO_PORT           GPIO_GetPort(OUTPUT_PIN)
   

2. The following macro can be configured to modify the timing.

   #define ENHTIM_UINT          40                            /*< 40M source clock is divided to get unit: 1us */
   #define ENHTIM_ING           1000000                       /*< Set this macro to 1000000, with a timer duration of 1s. the unit for this macro is in microseconds (us). */
   #define ENHTIM_PERIOD        ENHTIM_ING * ENHTIM_UINT
   

Building and Downloading

For building and downloading, please refer to the Building and Downloading.

Experimental Verification

1. When the EVB starts, observe the following log within the Debug Analyzer

   Start enhtim interrupt test!
   

2. After enabling ENHTIM, when each timer interval reaches 1 second, it will trigger the ENHTIM interrupt. Within the interrupt function, the output level of P0_0 is toggled, and LED0 can be observed to blink once every second.

Code Overview

This section mainly introduces the code and process description for initialization and corresponding function implementation in the sample.

Source Code Directory

The directory for project file and source code are as follows:

• Project directory: sdk\samples\peripheral\enhtimer\enhtim_interrupt\proj

• Source code directory: sdk\samples\peripheral\enhtimer\enhtim_interrupt\src

Initialization

The initialization flow for peripherals can refer to Initialization Flow in General Introduction.

1. Call Pad_Config() and Pinmux_Config() to configure the PAD and PINMUX of the corresponding pins.

   void board_gpio_init(void)
   {
       Pad_Config(OUTPUT_PIN, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_ENABLE, PAD_OUT_HIGH);
   
       Pinmux_Config(OUTPUT_PIN, DWGPIO);
   }
   

2. Call RCC_PeriphClockCmd() to enable the GPIO clock.

3. Initialize the GPIO peripheral:

   1. Define the GPIO_InitTypeDef type GPIO_InitStruct, and call GPIO_StructInit() to pre-fill GPIO_InitStruct with default values.

   2. Modify the GPIO_InitStruct parameters as needed. The initialization parameter configurations for GPIO are shown in the table below. Call GPIO_Init() to initialize the GPIO peripheral.

GPIO Initialization Parameters

GPIO Hardware Parameters	Setting in the GPIO_InitStruct	GPIO
GPIO pin	GPIO_InitTypeDef::GPIO_Pin	GPIO_PIN
GPIO direction	GPIO_InitTypeDef::GPIO_Dir	GPIO_DIR_OUT
GPIO interrupt	GPIO_InitTypeDef::GPIO_ITCmd	DISABLE

4. Call RCC_PeriphClockCmd() to enable the ENHTIM clock.

5. Initialize the ENHTIM peripheral:

   1. Define the ENHTIM_InitTypeDef type ENHTIM_InitStruct, and call ENHTIM_StructInit() to pre-fill ENHTIM_InitStruct with default values.

   2. Modify the ENHTIM_InitStruct parameters as needed. The initialization parameter configurations for ENHTIM are shown in the table below. Call ENHTIM_Init() to initialize the ENHTIM peripheral.

   3. Call NVIC_Init() to configure the NVIC. For NVIC-related configurations, refer to Interrupt Configuration.

   4. Call ENHTIM_ClearINTPendingBit() and ENHTIM_INTConfig() to clear the ENHTIM interrupt and enable the ENHTIM interrupt.

ENHTIM Initialization Parameters

ENHTIM Hardware Parameters	Setting in the ENHTIM_InitStruct	ENHTIM
Counter mode	ENHTIM_InitTypeDef::ENHTIM_Mode	ENHTIM_MODE_PWM_MANUAL
PWM mode	ENHTIM_InitTypeDef::ENHTIM_PWMOutputEn	DISABLE
Count value	ENHTIM_InitTypeDef::ENHTIM_MaxCount	ENHTIM_PERIOD

6. Call ENHTIM_Cmd() to enable the TIM peripheral.

Functional Implementation

After enabling the ENHTIM peripheral, ENHTIM starts timing. When the timer of ENH_TIM0 reaches its specified timing, it triggers an interrupt, and the program enters the interrupt handling function Enhanced_Timer0_Handler.

1. Clear the interrupt flag of ENH_TIM0 and disable ENH_TIM0.

2. Check the current state of the LED, and toggle the level of LED0.

void Enhanced_Timer0_Handler()
{
    ENHTIM_ClearINTPendingBit(ENHTIMER_NUM, ENHTIM_INT_TIM);
    ENHTIM_Cmd(ENHTIMER_NUM, DISABLE);
    if (!LED_Status)
    {
        GPIO_WriteBit(GPIO_PORT, GPIO_PIN, (BitAction)(1));
        LED_Status = 1;
    }
    else
    {
        GPIO_WriteBit(GPIO_PORT, GPIO_PIN, (BitAction)(0));
        LED_Status = 0;
    }
    //Add user code here
    ENHTIM_Cmd(ENHTIMER_NUM, ENABLE);
}