Output Toggle

This example is based on the output function of GPIO, implementing periodic state toggle control of the LED.

Configure the GPIO as output mode. Within the while loop, toggle the input level every 1 second to drive the LED to blink.

Users can modify pin information through different macro configurations. For specific macro configurations, refer to Configurations.

Requirements

For requirements, please refer to the Requirements.

Wiring

Connect P1_0 to LED0. The LED driver circuit is shown below.

Here should be a picture of the LED driver circuit — LED Driver Circuit Diagram

Configurations

The following macro can be configured to modify the pin definition.
```
#define OUTPUT_PIN              P1_0
```

Building and Downloading

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

Experimental Verification

After resetting the EVB, observe the log messages as shown in the Debug Analyzer.
```
Start gpio toggle test!
```
Observe that the LED is blinking.

Code Overview

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

Source Code Directory

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

Project directory: sdk\samples\peripheral\gpio\output_toggle\proj
Source code directory: sdk\samples\peripheral\gpio\output_toggle\src

Initialization

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

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);
}

Call RCC_PeriphClockCmd() to enable the GPIO clock.
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`

Functional Implementation

After initialization, call GPIO_WriteBit() within the while loop to control the GPIO output high and low levels.

while (1)
{
    /* Set GPIO_PIN_OUTPUT */
    GPIO_WriteBit(GPIO_PORT, GPIO_PIN, (BitAction)(1));
    platform_delay_ms(1000);
    /* Reset GPIO_PIN_OUTPUT */
    GPIO_WriteBit(GPIO_PORT, GPIO_PIN, (BitAction)(0));
    platform_delay_ms(1000);
}