Lecture 3 - GPIO input / output library function usage and related routines

Catalog

Preface

One 、 Add the missing content in the first lecture

1.stm32 Naming rules of development board ：

2. Model classification

Two .GPIO Input and output related library functions

1. Need to master first GPIO function

1.GPIO_SetBits() Function and GPIO_ResetBits function ：

2.GPIO_WriteBit Function and GPIO_Write function ：

2. Lighten up LED and LED flashing

---

Preface

The last lecture introduced GPIO What is it? ,GPIO Eight working modes of , In detail GPIO Initialize the configuration method , Here is a detailed introduction GPIO Input the usage of related library functions and use related routines for your reference

---

One 、 Add the missing content in the first lecture

When the project folder is established and the relevant library is imported , After the questions of the little partner, I found that I missed a more important content , That is how to choose according to the development board model user Startup file in , Let's give you a detailed introduction ：

1.stm32 Naming rules of development board ：

Want to know how to choose the right startup file , First of all, be clear stm32 Naming rules of series development boards , With what I use stm32f103c8t6 For example ,

Divide it into STM32 F 103C8 T6

Stm32 That is to say 32 Single chip microcomputer ,

F It's the product type ,103 Represents the product sub series ,101 Basic type ,102 by USB Basic type ,103 It is enhanced ,105 or 107 It is interconnected .

C Number of representative pins ,T=36 foot ,C=48 foot ,R=64 foot ,V=100 foot ,Z=144 foot .

8 representative FLASH size （ It can be understood as flash memory ）6=32K,8=64K,B=128K,C=256K,D=384K,E=512K

T Representative package H=BGA T=LQFP,U=VFQFPN

6 Represents the operating temperature range   6= Industrial grade ,-40~+85℃         7= Industrial grade ,-40~+105℃   

2. Model classification

Classify according to their model

model	Flash Capacity	abbreviation
STM32F100	16-32K	LD_VL
STM32F100	64-128K	MD_VL
STM32F100	256-512K	HD_VL
STM32F101/102/103	16-32K	LD
STM32F101/102/103	64-128K	MD
STM32F101/102/103	256-512K	HD
STM32F101/102/103	>512K	XL
STM32F105/107	--	CL

therefore , We use F103C8T6 Is it just a choice MD,s The startup file of :?

Obviously ！

Two .GPIO Input and output related library functions

First of all, let's talk about it GPIO The relevant library functions of input and output are in the GPIO.h In file , Drop down to the end to find .

1. Need to master first GPIO function

void GPIO_SetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
void GPIO_ResetBits(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin);
void GPIO_WriteBit(GPIO_TypeDef* GPIOx, uint16_t GPIO_Pin, BitAction BitVal);
void GPIO_Write(GPIO_TypeDef* GPIOx, uint16_t PortVal);

These are the most commonly used for beginners GPIO function , Let's introduce... One by one ：

1.GPIO_SetBits() Function and GPIO_ResetBits function ：

Used to configure GPIO The port is high level ,LED You can use this function to turn off the light in , Where the parameters of the function are the same as GPIO The parameters of the initialization function are the same , Another example is how to choose parameters , First look at the comments about parameters in the function definition .

  * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bits to be written.

Illustrate with examples , Suppose we connect peripherals to PA0 mouth , that GPIOx This parameter uses GPIOA, The second parameter is GPIO_Pin_0, So the parameter of this function is （GPIOA,GPIO_Pin_0）

The lower one GPIO_ResetBits Function is also this parameter selection method ,LED You can use this function to turn off the light in , And this function Used to configure GPIO The port is low level .

2.GPIO_WriteBit Function and GPIO_Write function ：

GPIO_WriteBit This function has three arguments , Unlike the above function , This function takes three arguments , This parameter is also an implementation GPIO High and low level setting of port , Here's an example ：

First look at the function parameter comments ：

 * @param  GPIOx: where x can be (A..G) to select the GPIO peripheral.
  * @param  GPIO_Pin: specifies the port bit to be written.
  *   This parameter can be one of GPIO_Pin_x where x can be (0..15).
  * @param  BitVal: specifies the value to be written to the selected bit.
  *   This parameter can be one of the BitAction enum values:
  *     @arg Bit_RESET: to clear the port pin
  *     @arg Bit_SET: to set the port pin

We still use A0 Take the mouth as an example ： Then the first and second parameters are the same as the function described above , Respectively GPIOA and GPIO_PIN_0, Focus on the third parameter , If you want to A0 Set the port to high level , That is, the setting port signal mentioned in the note （to set the port pin）, Parameter selection Bit_SET, conversely , That is to clear the port signal （to set the port pin）, The parameter is Bit_RESET.

Yes, of course , If you especially want to use 1 and 0 Indicates high and low level , It's fine too , But you need to do a forced conversion , Convert to BitAction, The third parameter is (（BitAction）1) or (（BitAction）0). But not recommended .

And the other function GPIO_Write, All ports can be operated , We will introduce this in detail in the next article .

2. Lighten up LED and LED flashing

After learning the above functions , It can be lit LED Operation , Let's just say LED flashing , It contains points LED The operation of .

First turn on the GPIO Initialization is complete , I already talked about it last class , Here we use , No, you can go to my last blog to have a look . And then use GPIO_SetBits() Lights out ,GPIO_ResetBits() Lighting , Adding delay is flashing .

The attached code ：

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
    

int main()
{
	
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);// Use RCC Turn on GPIO The clock 
	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // Push pull output 
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 ;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz ;
	GPIO_Init(GPIOA,&GPIO_InitStructure);
	// Up to the top ,GPIO Initialization complete 
	while(1)
	{
			GPIO_ResetBits(GPIOA,GPIO_Pin_0);
			GPIO_SetBits(GPIOA,GPIO_Pin_0);
			Delay_ms(500);
			GPIO_WriteBit(GPIOA,GPIO_Pin_0, Bit_RESET);
//GPIO_WriteBit(GPIOA,GPIO_Pin_0, (BitAction)0);
			Delay_ms(500);
			GPIO_WriteBit(GPIOA,GPIO_Pin_0, Bit_SET);	//GPIO_WriteBit(GPIOA,GPIO_Pin_0, (BitAction)1);
			Delay_ms(500);
	}

}