stm8s development (II) Use of GPIO: light up the LED!

The general purpose input and output port (GPIO) is the most basic port we use for microcontrollers. Its main functions are:

● Each bit of the port can be configured individually

● Selectable input mode: floating input and input with pull-up

● Selectable output modes: push-pull output and open-drain output

● External interrupts can be enabled and disabled individually

The user manual describes:

Each port has an output data register (ODR), a pin input register (IDR) and a data direction register (DDR) that are always associated. Control register 1 (CR1) and control register 2 (CR2) are used to configure the input/output. Any I/O pin can be configured by programming the corresponding bits of the DDR, ODR, CR1 and CR2 registers.

The various configurations are summarized below:

Here we use three LEDs as an exercise, namely PA1, PA2, and PD4, all of which are set to push-pull output mode.

Here is the initialization function:

1. //CTRL0 PA1  

2. //CTRL1 PA2  

3. //CTRL2 PD4  

4.   

5. void GPIO_init(void)  

6. {  

7.   PA_DDR|=0x03;  

8.   PA_CR1|=0x03;  

9.   PA_CR2|=0x00;  

10.     

11.   PD_DDR|=0x10;  

12.   PD_CR1|=0x10;  

13.   PD_CR2|=0x00;  

14. }  

If you need to control the level of the IO port, you need to modify the ODR register. By reading the table, you can know that 1 is a high level and 0 is a low level.

Here you only need to modify the value of the corresponding bit.

1. void CTRL0_HIGH(void)  

2. {  

3.   PA_ODR|=0x01;  

4. }  

5. void CTRL0_LOW(void)  

6. {  

7.   PA_ODR&=0xFE;  

8. }  

9. void CTRL0_Reverse(void)  

10. {  

11.   PA_ODR^=0x01;  

12. }  

Attached is the project of stm8s in IAR environment, including the initialization code of on-chip hardware such as SPI, IIC, PWM, AWU, USART, EEPROM, etc.

http://download.csdn.net/detail/devintt/9454188