Content of this article: This article mainly introduces the address configuration mode of the register and the code calling the register to light a string of water lamps.
catalogue
(3) Library function to realize water lamp
1, What is a register
In official terms, registers are some small storage areas used to store data in the CPU, which are used to temporarily store the data and operation results involved in the operation.
In short, if our computer is compared to a building, and the register is every house in the building, the register address can be regarded as the house number, but the house number is a little special, which is composed of 01 bit stream.
2, GPIO
(1) Introduction
(2) Working mode
typedef enum
{
GPIO_Mode_AIN = 0x0, // Analog input
GPIO_Mode_IN_FLOATING = 0x04, // Floating input
GPIO_Mode_IPD = 0x28, // Drop down input
GPIO_Mode_IPU = 0x48, // Pull up input
GPIO_Mode_Out_OD = 0x14, // Open drain output
GPIO_Mode_Out_PP = 0x10, // Push pull output
GPIO_Mode_AF_OD = 0x1C, // Multiplexed open drain output
GPIO_Mode_AF_PP = 0x18 // Multiplexed push-pull output
} GPIOMode_TypeDef;(3) Addressing of GPIO
For details, please move to the big man and speak clearly:
STM32 register introduction, address search, and direct operation register_ Geekyatao CSDN blog
3, Light up
(1) Assembly lighting
The following is the assembler for lighting the LED of PB5 connection:
Note: when selecting the operating environment, you do not need to check "Startup" and "CORE".
LED0 EQU 0x42218194
RCC_APB2ENR EQU 0x40021018
;GPIOA_CRH EQU 0x40010804
GPIOB_CRL EQU 0x40010C00
Stack_Size EQU 0x00000400
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE Stack_Size
__initial_sp
AREA RESET, DATA, READONLY
__Vectors DCD __initial_sp
DCD Reset_Handler
AREA |.text|, CODE, READONLY
THUMB
REQUIRE8
PRESERVE8
ENTRY
Reset_Handler
BL LED_Init
MainLoop BL LED_ON
BL Delay
BL LED_OFF
BL Delay
B MainLoop
LED_Init
PUSH {R0,R1, LR}
LDR R0,=RCC_APB2ENR
ORR R0,R0,#0x08
LDR R1,=RCC_APB2ENR
STR R0,[R1]
LDR R0,=GPIOB_CRL
BIC R0,R0,#0XFF0FFFFF
LDR R1,=GPIOB_CRL
STR R0,[R1]
LDR R0,=GPIOB_CRL
ORR R0,R0,#0X00300000
LDR R1,=GPIOB_CRL
STR R0,[R1]
MOV R0,#1
LDR R1,=LED0
STR R0,[R1]
POP {R0,R1,PC}
LED_ON
PUSH {R0,R1, LR}
MOV R0,#0
LDR R1,=LED0
STR R0,[R1]
POP {R0,R1,PC}
LED_OFF
PUSH {R0,R1, LR}
MOV R0,#1
LDR R1,=LED0
STR R0,[R1]
POP {R0,R1,PC}
Delay
PUSH {R0,R1, LR}
MOVS R0,#0
MOVS R1,#0
MOVS R2,#0
DelayLoop0
ADDS R0,R0,#1
CMP R0,#330
BCC DelayLoop0
MOVS R0,#0
ADDS R1,R1,#1
CMP R1,#330
BCC DelayLoop0
MOVS R0,#0
MOVS R1,#0
ADDS R2,R2,#1
CMP R2,#15
BCC DelayLoop0
POP {R0,R1,PC}
END
Next, use mcuisp to burn the program
Burning succeeded
Here are the connections:
Connect one end of LED to PB5 and one end to 3.3V
Note: it's best not to connect 5V. There is no resistance protection. The author has burned several
Here I use the STM32F103RC small blackboard I bought when preparing for the video game
The effect is shown in the figure:
(2) C language lighting
I changed it with the lighting program of punctual atom. Because there are too many documents, only some main documents are listed below
The code is as follows:
test.c
#include "sys.h"
#include "usart.h"
#include "delay.h"
#include "led.h"
int main(void)
{
Stm32_Clock_Init(9); //System clock setting
delay_init(72); //Delay initialization
LED_Init(); //LED initialization
while(1)
{
LED0=0;
delay_ms(1000); //Delay 1s
LED0=1;
delay_ms(1000);
}
}led.h
#ifndef __LED_H #define __LED_H #include "sys.h" #define LED0 PAout(8) // PA8 void LED_Init(void); #endif
led.c
#include "sys.h"
#include "led.h"
//LED IO initialization
void LED_Init(void)
{
RCC->APB2ENR|=1<<2; //Enable PORTA clock
GPIOA->CRH&=0XFFFFFFF0;
GPIOA->CRH|=0X00000003;//PA8 push pull output
GPIOA->ODR|=1<<8; //PA8 output high
}Both ends of the LED are connected to PA8 and 3.3V respectively
The effect is shown in the figure:
(3) Library function to realize water lamp
Compared with the register code, the library function is more readable and more convenient to use. This is also the way the author has been using before. Let's write a flow lamp with the library function
The code is as follows:
main.c
#include "led.h"
#include "delay.h"
#include "sys.h"
int main(void)
{
delay_init(); //Delay function initialization
LED_Init(); //LED initialization
while(1)
{
LED0=0;
delay_ms(1000); //Delay 1s
LED0=1;
delay_ms(1000);
LED1=0;
delay_ms(1000);
LED1=1;
delay_ms(1000);
LED2=0;
delay_ms(1000);
LED2=1;
delay_ms(1000);
}
}led.h
#ifndef __LED_H #define __LED_H #include "sys.h" #define LED0 PAout(6) // PA6 #define LED1 PBout(7) // PA7 #define LED2 PBout(8) // PA8 void LED_Init(void); #endif
led.c
#include "led.h"
//LED IO³õʼ»¯
void LED_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //Enable PB port clock
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_8; //PB6,PB7,PB8 port configuration
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; //Push pull output
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //The IO speed is 50MHz
GPIO_Init(GPIOB, &GPIO_InitStructure); //Initialize GPIOB according to the setting function
GPIO_SetBits(GPIOB,GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_8); //PB6,PB7,PB8 output high
}Three LEDs are used here. The long pin of each LED is connected to 3.3V and the short pin is connected to pb6, 7 and 8 respectively
The effect of hardware is as follows:
4, Summary
This experiment mainly carried out the LED register lighting experiment. Before, it had been written with library functions and had not used registers. This time, I really felt its cumbersome use, especially the GPIO address. I also needed to consult the manual, which was very poor in readability and encountered many difficulties in the programming process. However, I also learned the addressing principle of registers by consulting materials, Although cumbersome, it feels good to communicate with the computer more intuitively.
5, Reference articles
STM32 assembler and lighting experiment_ Lxy1360832244 blog - CSDN blog
STM32 register introduction, address search, and direct operation register_ Geekyatao CSDN blog