STM8 study notes (I): GPIO

 I worked on it all night... but got nothing.

Maybe influenced by STM32, I always wanted to use its own library, but I was depressed for a long time.

No, without its own library

I went online to look up a routine for operating an LED.

I looked at several GPIO registers myself

There are mainly the following

1. Port x output data register (Px_ODR)

In output mode, the value written to the register is added to the corresponding pin through the latch. Reading the ODR register returns the previously latched register value.
In input mode, the value written to the ODR will be latched into the register, but will not change the pin state. The ODR register is always 0 after reset. Bit manipulation instructions (BSET, BRST) can be used to set the DR register to drive the corresponding pin, but will not affect other pins.
 

2. Port x input register (Px_IDR)

IDR[7:0]: Port input data register bit
Whether the pin is in input or output mode, the pin status value can be read through this register. This register is a read-only register.
0: logic low level
1: logic high level
 

3. Port x data direction (Px_DDR)

These bits can be set to 1 or 0 by software to select the pin as input or output
0: Input mode
1: Output mode
 

4. Port x Control Register 1 (Px_CR1)

In input mode (DDR=0):
0: floating input
1: input with pull-up resistor
In output mode (DDR=1):
0: simulated open-drain output (not true open-drain output)
1: push-pull output, output slew rate controlled by the corresponding bit of CR2
 

5. Port x control register 2 (Px_CR2) in input mode (DDR=0):

0: Disable external interrupt
1: Enable external interrupt
In output mode (DDR=1):
0: Maximum output speed is 2MHZ.
1: Maximum output speed is 10MHZ
 

The IDE I use is STVD. After creating a new project, put the STM8S208R.h library file in the newly created file

The following is programming

This is the code I wrote... It's pretty bad

///////////////////////////////////////////////////////////

/*============================================================================*/
/* PROJECT: LED Control by timer OC */
/* MODULE: main.c */
/* COMPILER: STM8 Cosmic C Compiler */
/* DATE: Feb 2009 */
/*----------------------------------------------------------------------------*/
/* DESCRIPTION: Demonstration firmware for STM8 Mini Kit */
/* Control LED blink, on/off/, brightness. */
/*============================================================================*/
/******************************************************************************
*
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
* TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
* DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
* FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
* CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
*
* COPYRIGHT 2008 STMicroelectronics
******************************************************************************
*/

/* Includes ------------------------------------------------------------------*/
#include "stm8s208r.h" /* Registers and memory mapping file. */

/******************************************************************************/
/* Function definitions */
/******************************************************************************/
/* -------------------------------------------------------------------------- */
/* ROUTINE NAME: GPIO_Init */
/* INPUT/OUTPUT: None. */
/* DESCRIPTION: Initialize GPIOs. */
/* IN: None. */
/* OUT: None. */
/* -------------------------------------------------------------------------- */
void GPIO_Init(void) 
{
/* LED IO Configuration */
/* LD3: PD3 */
/* LD2: PD1 */
/* LD1: PD0 */
PD_DDR |= 0xFF; /* Output. */
PD_CR1 |= 0xFF; /* PushPull. */
PD_CR2 = 0x00; /* Output speed up to 2MHz. */
PD_ODR |= 0x55;//IO口要输出的数据
}
/* -------------------------------------------------------------------------- */
/* ROUTINE NAME: CLK_Init */
/* INPUT/OUTPUT: None. */
/* DESCRIPTION: Initialize the clock source */
/* -------------------------------------------------------------------------- */
void CLK_Init(void)
{
/* Configure HSI prescaler*/
CLK_CKDIVR &= ~0x10; /* 01: fHSI= fHSI RC output/2. */

/* Configure CPU clock prescaler */
CLK_CKDIVR |= 0x01; /* 001: fCPU=fMASTER/2. */
}
/* -------------------------------------------------------------------------- */
/* ROUTINE: main */
/* main entry */
/* -------------------------------------------------------------------------- */
void main ( void )
{ 
while(1)
{
CLK_Init();
GPIO_Init();
}
} 
/*---------------------------- End of file -----------------------------------*/

////////////////////////////////////////////////////////////////

This is just a very simple function

The road is long and arduous, and there is still a long way to go