[STM32 learning] (16) STM32 realizes LCD1602 display (74HC595 drive) - 4-bit bus

Use 74HC595 The purpose of the chip is actually very simple , Is to save STM32 Of IO mouth .

If not used 74HC595 modular , We are going to use D0-D7 Eight data pins , also RS,RW,EN Control pin , That means a lot IO foot , This is not convenient STM32 Expansion of other functions or modules , Is not desirable . While using 595 Module can solve this problem well .

The model of single chip microcomputer used ：STM32L052K8*

LCD module ：RG1602A, Actually sum LCD1602 It's the same .

connection , Here's the picture （ Very important ）：

You will find that you only need to 74HC595 The three pins of are connected to STM32 Just go up , But just a hint , It's not necessary to answer PB1、PA5、PA7, In fact, it's up to you to answer , You need to modify the code .

1.LCD1602 The implementation of the

 

       ||* It can be found that only 4 Bit control line realizes data transmission

                  How to realize transmission ？   —— If you want to transmit one byte of data , You need to transmit this byte first Senior four , Then transmit the... Of this byte Four lower .

According to the configuration RS and EN To carry out Writing data or Write orders .

      About LCD1602 The pin and function information of are also covered in previous blogs , You can see my previous blog .

  2.74HC595 Realize serial parallel output

       ||* Data transmission

                  This is also mentioned in the previous blog , You can check the previous blog . We must pay attention to the relationship of time sequence .

About IO Initialization configuration of port , as follows ：

static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOA, SCLK_Pin|DATA_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(RCLK_GPIO_Port, RCLK_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pins : SCLK_Pin DATA_Pin */
  GPIO_InitStruct.Pin = SCLK_Pin|DATA_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /*Configure GPIO pin : RCLK_Pin */
  GPIO_InitStruct.Pin = RCLK_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(RCLK_GPIO_Port, &GPIO_InitStruct);

}

lcd1602.c

#include "lcd1602.h"   
#include "stdio.h" 
#include "main.h"

/**********************************/
/**  The name of the function ：void LCD1602_Send595OneByte(unsigned char dis_data) **/
/**  Input parameters ：unsigned char dis_data  Data to be entered   */
/**  The functionality ： Write the data into 74HC595 in */
/** ****************************** **/
void LCD1602_Send595OneByte(unsigned char dis_data)
{
	unsigned char i;
	unsigned char temp;
	temp = dis_data;
	for(i=0;i<8;i++)
	{
		HAL_GPIO_WritePin(SCLK_GPIO_Port,SCLK_Pin,GPIO_PIN_RESET);	
		if(temp & 0X80)
		{
			HAL_GPIO_WritePin(DATA_GPIO_Port,DATA_Pin,GPIO_PIN_SET);
		}
		else
		{
			HAL_GPIO_WritePin(DATA_GPIO_Port,DATA_Pin,GPIO_PIN_RESET);
		}
		temp = temp<<1;
		HAL_GPIO_WritePin(SCLK_GPIO_Port,SCLK_Pin,GPIO_PIN_RESET);		//	0
		HAL_GPIO_WritePin(SCLK_GPIO_Port,SCLK_Pin,GPIO_PIN_SET);			//	1
		HAL_GPIO_WritePin(SCLK_GPIO_Port,SCLK_Pin,GPIO_PIN_RESET);		//	0
	}
}

/****************************************/
/** The name of the function ：void LCD1602_OUT(void)			*/
/** Function parameter ： No arguments 							*/
/** The functionality ： Register data output display 			*/
void LCD1602_OUT(void)
{
	HAL_GPIO_WritePin(RCLK_GPIO_Port,RCLK_Pin,GPIO_PIN_RESET);
	HAL_GPIO_WritePin(RCLK_GPIO_Port,RCLK_Pin,GPIO_PIN_SET);
	HAL_GPIO_WritePin(RCLK_GPIO_Port,RCLK_Pin,GPIO_PIN_RESET);
}


/*  towards LCD1602 LCD write one byte command ,cmd- Command value to be written  */
// LCD write instructions 
void LCD1602_Write_Command(uint8_t command)
{
	LCD1602_Send595OneByte(0x02);								//LCD1602_EN=1,LCD1602_RS=0, Qinggao 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x02|(((command & 0xf0)>>4)<<2));	//LCD1602_EN=1,LCD1602_RS=0, Write high 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x00|(((command & 0xf0)>>4)<<2));	//LCD1602_EN=0,LCD1602_RS=0, Write high 4 position 
	LCD1602_OUT();
	
	command = command << 4;										// low 4 Shift to high 4 position 
	LCD1602_Send595OneByte(0x02);								//LCD1602_EN=1,LCD1602_RS=0, Qinggao 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x02|(((command & 0xf0)>>4)<<2));	//LCD1602_EN=1,LCD1602_RS=0, Write down 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x00|(((command & 0xf0)>>4)<<2));	//LCD1602_EN=0,LCD1602_RS=0, Write down 4 position 
	LCD1602_OUT();
}

// LCD write data 
void LCD1602_Write_Data(uint8_t RecData)
{

	LCD1602_Send595OneByte(0x03);								//LCD1602_EN=1,LCD1602_RS=1, Qinggao 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x03|(((RecData & 0xf0)>>4)<<2));	//LCD1602_EN=1,LCD1602_RS=1, Write high 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x01|(((RecData & 0xf0)>>4)<<2));	//LCD1602_EN=0,LCD1602_RS=1, Write high 4 position 
	LCD1602_OUT();
	
	RecData = RecData << 4;										// low 4 Shift to high 4 position 
	LCD1602_Send595OneByte(0x03);								//LCD1602_EN=1,LCD1602_RS=1, Qinggao 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x03|(((RecData & 0xf0)>>4)<<2));	//LCD1602_EN=1,LCD1602_RS=1, Write down 4 position 
	LCD1602_OUT();
	LCD1602_Send595OneByte(0x01|(((RecData & 0xf0)>>4)<<2));	//LCD1602_EN=0,LCD1602_RS=1, Write down 4 position 
	LCD1602_OUT();
}

/*  Clear the screen  */
void LCD1602_ClearScreen(void)
{
	LCD1602_Write_Command(0x01);
}

/*  Set display RAM Initial address , That is, the cursor position ,(x,y)- Corresponding to the character coordinates on the screen  */
void LCD1602_Set_Cursor(uint8_t x, uint8_t y)
{
	uint8_t addr;
	
	if (y == 0)
		addr = 0x00 + x;
	else
		addr = 0x40 + x;
	LCD1602_Write_Command(addr | 0x80);
}

/*  Display string on LCD ,(x,y)- Corresponding to the starting coordinates on the screen ,str- String pointer  */
void LCD1602_Show_Str(uint8_t x, uint8_t y, uint8_t *str)
{
	LCD1602_Set_Cursor(x, y);
	while(*str != '\0')
	{
		LCD1602_Write_Data(*str++);
	}
}

/*  initialization 1602 liquid crystal  */
void LCD1602_Init(void)
{
	LCD1602_Write_Command(0x33);	// original 1602 Initialize to 4 The bit data line must be initialized to 8 position ( At this time, the command sending method is 8 Bit format , But the data cable only needs to be connected 4 position )
	LCD1602_Write_Command(0x32);	// Then change to 4 Bit line width , In this way, the initialization is stable 
	LCD1602_Write_Command(0x28);	// Four wire mode setting 
	LCD1602_Write_Command(0x0c);	// Show on   
	LCD1602_Write_Command(0x01);	// Clear the screen 
	HAL_Delay(10);    
  
}

lcd1602.h

#include "main.h"
#ifndef __LCD1602_H
#define __LCD1602_H	 


void LCD1602_Send595OneByte(unsigned char dis_data);
void LCD1602_OUT(void);

void LCD1602_Wait_Ready(void);
void LCD1602_Write_Command(uint8_t cmd);
void LCD1602_Write_Data(uint8_t dat);
void LCD1602_ClearScreen(void);
void LCD1602_Set_Cursor(uint8_t x, uint8_t y);
void LCD1602_Show_Str(uint8_t x, uint8_t y, uint8_t *str);
void LCD1602_Init(void);

#endif

main.c

int main(void)
{
  
  uint8_t str[] = "   WANGTING";
  SystemClock_Config(); 
  MX_GPIO_Init();

  LCD1602_Init();
  LCD1602_Show_Str(1, 0, str);
  LCD1602_Show_Str(2, 1, "I LOVE STM32");
 
  while (1)
  {
   
  }
  
}

The effect is as follows ：