目录
测试代码下载地址：
stm32-f407-lcd-ft6336-proj资源-CSDN文库
gitee下载地址：
https://gitee.com/mftang/stm32_open_test_proj/tree/master/stm32_f407_lcd_proj概述
本文主要讲述使用模拟SPI接口驱动ST7796-LCD，主控MCU为STM32F407芯片。笔者详细介绍整个驱动的实现过程，并使用STM32Cube生成一个工程，测试驱动程序的功能。
1. 硬件介绍
1.1 ST7796-LCD
LCD的PIN引脚功能介绍
| 序号 | 模块引脚 | 引脚说明 |
| 1 | VCC | 屏电源正 |
| 2 | GND | 屏电源地 |
| 3 | LCD_CS | 液晶屏片选控制信号，低电平有效 |
| 4 | LCD_RST | 液晶屏复位控制信号，低电平复位 |
| 5 | LCD_RS | 液晶屏命令/数据选择控制信号 高电平：数据，低电平：命令 |
| 6 | SDI(MOSI) | SPI总线写数据信号（SD卡和液晶屏共用） |
| 7 | SCK | SPI总线时钟信号（SD卡和液晶屏共用） |
| 8 | LED | 液晶屏背光控制信号（如需要控制，请接引脚，如不需要控制，可以不接） |
| 9 | SDO(MISO) | SPI总线读数据信号（SD卡和液晶屏共用） |
| 10 | CTP_SCL | 电容触摸屏IIC总线时钟信号（无触摸屏的模块不需连接） |
| 11 | CTP_RST | 电容触摸屏复位控制信号，低电平复位（无触摸屏的模块不需连接） |
| 12 | CTP_SDA | 电容触摸屏IIC总线数据信号（无触摸屏的模块不需连接） |
| 13 | CTP_INT | 电容触摸屏IIC总线触摸中断信号，产生触摸时，输入低电平到主控（无触摸屏的模块不需连接） |
| 14 | SD_CS | SD卡片选控制信号，低电平有效（不使用SD卡功能，可不接） |
实体LCD Port对应关系如下图所示
1.2 MCU IO与LCD PIN对应关系
| STM32 PIN引脚 | LCD PIN引脚 |
|---|---|
| PB5-MOSI | MOSI |
| PB4-MISO | MISO |
| PB3-SCK | SCK |
| PB6 | CS |
| PB9 | RST |
| PB8 | RS |
2 代码实现
2.1 STM32CubeMX 6.11生成工程
笔者尝试使用IO模拟SPI接口，以实现读写数据功能，其配置接口信息如下：
step-1： 配LCD对应的IO
step-2: 使能外部时钟
配置完成后，系统时钟关系如下：
step-3: 生成工程
2.2 IO模拟SPI接口
1）头文件里定义MOSI,SCK和MISO的电平状态
#ifndef __LCD_SPI_H
#define __LCD_SPI_H
#include <stdlib.h>
#include <stdio.h>
#include "main.h"
// spi port io
// set IO to high
#define SPI_SCLK_SET HAL_GPIO_WritePin(lcd_sck_GPIO_Port,lcd_sck_Pin, GPIO_PIN_SET )
#define SPI_MOSI_SET HAL_GPIO_WritePin(lcd_mosi_GPIO_Port,lcd_mosi_Pin, GPIO_PIN_SET )
// set IO to low
#define SPI_SCLK_CLR HAL_GPIO_WritePin(lcd_sck_GPIO_Port,lcd_sck_Pin, GPIO_PIN_RESET )
#define SPI_MOSI_CLR HAL_GPIO_WritePin(lcd_mosi_GPIO_Port,lcd_mosi_Pin, GPIO_PIN_RESET )
#define SPI_MISO_READ ((HAL_GPIO_ReadPin(lcd_miso_GPIO_Port, lcd_miso_Pin) == GPIO_PIN_SET)?1:0)
void SPI_WriteByte(uint8_t Byte);
uint8_t SPI_ReadByte(void);
void lcd_delay_us(uint32_t us);
#endif /* __LCD_SPI_H */2）实现SPI的读写接口
#include "lcd_spi.h"
void lcd_delay_us(uint32_t us)
{
uint32_t i=0;
while(us--){
for(i=0;i<1000;i++);
}
}
void SPI_WriteByte(uint8_t Byte)
{
uint8_t i=0;
for(i=0;i<8;i++)
{
if(Byte&0x80)
{
SPI_MOSI_SET;
}
else
{
SPI_MOSI_CLR;
}
SPI_SCLK_CLR;
SPI_SCLK_SET;
Byte<<=1;
}
}
uint8_t SPI_ReadByte(void)
{
uint8_t value=0,i=0,byte=0xFF;
for(i=0;i<8;i++)
{
value<<=1;
if(byte&0x80)
{
SPI_MOSI_SET;
}
else
{
SPI_MOSI_CLR;
}
byte<<=1;
SPI_SCLK_CLR;
lcd_delay_us(100);
if(SPI_MISO_READ)
{
value += 1;
}
SPI_SCLK_SET;
lcd_delay_us(100);
}
return value;
} 2.3 实现LCD的驱动
在该文件中实现初始化LCD，读写point等接口函数
#include "lcd_drv.h"
#include "lcd_spi.h"
_lcd_dev lcddev;
void LCD_WR_REG(uint8_t data)
{
LCD_CS_CLR;
LCD_RS_CLR;
SPI_WriteByte(data);
LCD_CS_SET;
}
void LCD_WR_DATA(uint8_t data)
{
LCD_CS_CLR;
LCD_RS_SET;
SPI_WriteByte(data);
LCD_CS_SET;
}
uint8_t LCD_RD_DATA(void)
{
uint8_t data;
LCD_CS_CLR;
LCD_RS_SET;
data = SPI_ReadByte();
LCD_CS_SET;
return data;
}
void LCD_WriteReg(uint8_t LCD_Reg, uint16_t LCD_RegValue)
{
LCD_WR_REG(LCD_Reg);
LCD_WR_DATA(LCD_RegValue);
}
uint8_t LCD_ReadReg(uint8_t LCD_Reg)
{
LCD_WR_REG(LCD_Reg);
return LCD_RD_DATA();
}
void LCD_WriteRAM_Prepare(void)
{
LCD_WR_REG(lcddev.wramcmd);
}
void Lcd_WriteData_16Bit(uint16_t Data)
{
LCD_CS_CLR;
LCD_RS_SET;
SPI_WriteByte(Data>>8);
SPI_WriteByte(Data);
LCD_CS_SET;
}
uint16_t Lcd_ReadData_16Bit(void)
{
uint16_t r,g;
LCD_CS_CLR;
LCD_RS_CLR;
SPI_WriteByte(lcddev.rramcmd);
LCD_RS_SET;
SPI_ReadByte();
r = SPI_ReadByte();
g = SPI_ReadByte();
LCD_CS_SET;
r<<=8;
r|=g;
return r;
}
void LCD_DrawPoint(uint16_t x,uint16_t y, uint16_t color)
{
LCD_SetCursor(x,y); //set the position
Lcd_WriteData_16Bit(color);
}
uint16_t LCD_ReadPoint(uint16_t x,uint16_t y)
{
uint16_t color;
LCD_SetCursor(x,y); //set the position
color = Lcd_ReadData_16Bit();
return color;
}
void LCD_Clear(uint16_t Color)
{
uint16_t i,m;
LCD_SetWindows(0,0,lcddev.width-1,lcddev.height-1);
LCD_CS_CLR;
LCD_RS_SET;
for(i=0;i<lcddev.height;i++)
{
for(m=0;m<lcddev.width;m++)
{
SPI_WriteByte(Color>>8);
SPI_WriteByte(Color);
}
}
LCD_CS_SET;
}
void LCD_SetWindows(uint16_t xStar, uint16_t yStar,uint16_t xEnd,uint16_t yEnd)
{
LCD_WR_REG(lcddev.setxcmd);
LCD_WR_DATA(xStar>>8);
LCD_WR_DATA(0x00FF&xStar);
LCD_WR_DATA(xEnd>>8);
LCD_WR_DATA(0x00FF&xEnd);
LCD_WR_REG(lcddev.setycmd);
LCD_WR_DATA(yStar>>8);
LCD_WR_DATA(0x00FF&yStar);
LCD_WR_DATA(yEnd>>8);
LCD_WR_DATA(0x00FF&yEnd);
LCD_WriteRAM_Prepare(); // prepare the RAM
}
void LCD_SetCursor(uint16_t Xpos, uint16_t Ypos)
{
LCD_SetWindows(Xpos,Ypos,Xpos,Ypos);
}
void LCD_direction(uint8_t direction)
{
lcddev.setxcmd=0x2A;
lcddev.setycmd=0x2B;
lcddev.wramcmd=0x2C;
lcddev.rramcmd=0x2E;
lcddev.dir = direction%4;
switch(lcddev.dir){
case 0:
lcddev.width=LCD_W;
lcddev.height=LCD_H;
LCD_WriteReg(0x36,(1<<3)|(1<<6));
break;
case 1:
lcddev.width=LCD_H;
lcddev.height=LCD_W;
LCD_WriteReg(0x36,(1<<3)|(1<<5));
break;
case 2:
lcddev.width=LCD_W;
lcddev.height=LCD_H;
LCD_WriteReg(0x36,(1<<3)|(1<<7));
break;
case 3:
lcddev.width=LCD_H;
lcddev.height=LCD_W;
LCD_WriteReg(0x36,(1<<3)|(1<<7)|(1<<6)|(1<<5));
break;
default:break;
}
}
uint16_t LCD_Read_ID(void)
{
uint8_t i,val[3] = {0};
LCD_WR_REG(0xF0); // Command Set Control
LCD_WR_DATA(0xC3);
LCD_WR_REG(0xF0);
LCD_WR_DATA(0x96);
LCD_CS_CLR;
for(i=1;i<4;i++)
{
LCD_RS_CLR;
SPI_WriteByte(0xFB);
LCD_RS_SET;
SPI_WriteByte(0x10+i);
LCD_RS_CLR;
SPI_WriteByte(0xD3);
LCD_RS_SET;
val[i-1] = SPI_ReadByte();
LCD_RS_CLR;
SPI_WriteByte(0xFB);
LCD_RS_SET;
SPI_WriteByte(0x00);
}
LCD_CS_SET;
LCD_WR_REG(0xF0); // Command Set Control
LCD_WR_DATA(0x3C);
LCD_WR_REG(0xF0);
LCD_WR_DATA(0x69);
lcddev.id=val[1];
lcddev.id<<=8;
lcddev.id|=val[2];
return lcddev.id;
}
void LCD_RESET(void)
{
LCD_RST_CLR;
lcd_delay_us(100);
LCD_RST_SET;
lcd_delay_us(50);
}
void LCD_Init(void)
{
LCD_RESET(); // reset the LCD
//*************3.5 ST7796S IPS pannel **********
LCD_WR_REG(0x11);
lcd_delay_us(120); //Delay 120ms
lcd_delay_us(120); //Delay 120ms
LCD_WR_REG(0x36); // Memory Data Access Control MY,MX~~
LCD_WR_DATA(0x48);
LCD_WR_REG(0x3A);
LCD_WR_DATA(0x55);
LCD_WR_REG(0xF0); // Command Set Control
LCD_WR_DATA(0xC3);
LCD_WR_REG(0xF0);
LCD_WR_DATA(0x96);
LCD_WR_REG(0xB4);
LCD_WR_DATA(0x01);
LCD_WR_REG(0xB7);
LCD_WR_DATA(0xC6);
//LCD_WR_REG(0xB9);
//LCD_WR_DATA(0x02);
//LCD_WR_DATA(0xE0);
LCD_WR_REG(0xC0);
LCD_WR_DATA(0x80);
LCD_WR_DATA(0x45);
LCD_WR_REG(0xC1);
LCD_WR_DATA(0x13); //18 //00
LCD_WR_REG(0xC2);
LCD_WR_DATA(0xA7);
LCD_WR_REG(0xC5);
LCD_WR_DATA(0x0A);
LCD_WR_REG(0xE8);
LCD_WR_DATA(0x40);
LCD_WR_DATA(0x8A);
LCD_WR_DATA(0x00);
LCD_WR_DATA(0x00);
LCD_WR_DATA(0x29);
LCD_WR_DATA(0x19);
LCD_WR_DATA(0xA5);
LCD_WR_DATA(0x33);
LCD_WR_REG(0xE0);
LCD_WR_DATA(0xD0);
LCD_WR_DATA(0x08);
LCD_WR_DATA(0x0F);
LCD_WR_DATA(0x06);
LCD_WR_DATA(0x06);
LCD_WR_DATA(0x33);
LCD_WR_DATA(0x30);
LCD_WR_DATA(0x33);
LCD_WR_DATA(0x47);
LCD_WR_DATA(0x17);
LCD_WR_DATA(0x13);
LCD_WR_DATA(0x13);
LCD_WR_DATA(0x2B);
LCD_WR_DATA(0x31);
LCD_WR_REG(0xE1);
LCD_WR_DATA(0xD0);
LCD_WR_DATA(0x0A);
LCD_WR_DATA(0x11);
LCD_WR_DATA(0x0B);
LCD_WR_DATA(0x09);
LCD_WR_DATA(0x07);
LCD_WR_DATA(0x2F);
LCD_WR_DATA(0x33);
LCD_WR_DATA(0x47);
LCD_WR_DATA(0x38);
LCD_WR_DATA(0x15);
LCD_WR_DATA(0x16);
LCD_WR_DATA(0x2C);
LCD_WR_DATA(0x32);
LCD_WR_REG(0xF0);
LCD_WR_DATA(0x3C);
LCD_WR_REG(0xF0);
LCD_WR_DATA(0x69);
lcd_delay_us(120);
LCD_WR_REG(0x21);
LCD_WR_REG(0x29);
LCD_direction(USE_HORIZONTAL); // set the driection
LCD_Clear(GREEN); // clear the screen as green
}
/* End of this file */
该driver对应的头文件：
#ifndef __LCD_DRV_H
#define __LCD_DRV_H
#include <stdlib.h>
#include <stdio.h>
#include "main.h"
//LCD重要参数集
typedef struct
{
uint16_t width; //LCD 宽度
uint16_t height; //LCD 高度
uint16_t id; //LCD ID
uint8_t dir; //横屏还是竖屏控制：0，竖屏；1，横屏。
uint16_t wramcmd; //开始写gram指令
uint16_t rramcmd; //开始读gram指令
uint16_t setxcmd; //设置x坐标指令
uint16_t setycmd; //设置y坐标指令
}_lcd_dev;
//LCD参数
extern _lcd_dev lcddev; //管理LCD重要参数
/用户配置区///
#define USE_HORIZONTAL 0//定义液晶屏顺时针旋转方向 0-0度旋转，1-90度旋转，2-180度旋转，3-270度旋转
//
//定义LCD的尺寸
#define LCD_W 320
#define LCD_H 480
//如果使用官方库函数定义下列底层，速度将会下降到14帧每秒，建议采用我司推荐方法
//以下IO定义直接操作寄存器，快速IO操作，刷屏速率可以达到28帧每秒！
#define LCD_CS_SET HAL_GPIO_WritePin(lcd_cs_GPIO_Port,lcd_cs_Pin, GPIO_PIN_SET )
#define LCD_RS_SET HAL_GPIO_WritePin(lcd_rs_GPIO_Port,lcd_rs_Pin, GPIO_PIN_SET )
#define LCD_RST_SET HAL_GPIO_WritePin(lcd_rst_GPIO_Port,lcd_rst_Pin, GPIO_PIN_SET )
#define LCD_CS_CLR HAL_GPIO_WritePin(lcd_cs_GPIO_Port,lcd_cs_Pin, GPIO_PIN_RESET )
#define LCD_RS_CLR HAL_GPIO_WritePin(lcd_rs_GPIO_Port,lcd_rs_Pin, GPIO_PIN_RESET )
#define LCD_RST_CLR HAL_GPIO_WritePin(lcd_rst_GPIO_Port,lcd_rst_Pin, GPIO_PIN_RESET )
//画笔颜色
#define WHITE 0xFFFF
#define BLACK 0x0000
#define BLUE 0x001F
#define BRED 0XF81F
#define GRED 0XFFE0
#define GBLUE 0X07FF
#define RED 0xF800
#define MAGENTA 0xF81F
#define GREEN 0x07E0
#define CYAN 0x7FFF
#define YELLOW 0xFFE0
#define BROWN 0XBC40 //棕色
#define BRRED 0XFC07 //棕红色
#define GRAY 0X8430 //灰色
//GUI颜色
#define DARKBLUE 0X01CF //深蓝色
#define LIGHTBLUE 0X7D7C //浅蓝色
#define GRAYBLUE 0X5458 //灰蓝色
//以上三色为PANEL的颜色
#define LIGHTGREEN 0X841F //浅绿色
#define LIGHTGRAY 0XEF5B //浅灰色(PANNEL)
#define LGRAY 0XC618 //浅灰色(PANNEL),窗体背景色
#define LGRAYBLUE 0XA651 //浅灰蓝色(中间层颜色)
#define LBBLUE 0X2B12 //浅棕蓝色(选择条目的反色)
void LCD_Init(void);
void LCD_DisplayOn(void);
void LCD_DisplayOff(void);
void LCD_Clear(uint16_t Color);
void LCD_SetCursor(uint16_t Xpos, uint16_t Ypos);
void LCD_DrawPoint(uint16_t x,uint16_t y, uint16_t color);
uint16_t LCD_ReadPoint(uint16_t x,uint16_t y); //读点
void LCD_DrawLine(uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2);
void LCD_DrawRectangle(uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2);
void LCD_SetWindows(uint16_t xStar, uint16_t yStar,uint16_t xEnd,uint16_t yEnd);
uint8_t LCD_RD_DATA(void); //读取LCD数据
void LCD_WriteReg(uint8_t LCD_Reg, uint16_t LCD_RegValue);
void LCD_WR_DATA(uint8_t data);
uint8_t LCD_ReadReg(uint8_t LCD_Reg);
void LCD_WriteRAM_Prepare(void);
void LCD_WriteRAM(uint16_t RGB_Code);
uint16_t LCD_ReadRAM(void);
uint16_t LCD_BGR2RGB(uint16_t c);
void LCD_SetParam(void);
void Lcd_WriteData_16Bit(uint16_t Data);
void LCD_direction(uint8_t direction );
uint16_t LCD_Read_ID(void);
#endif /* __LCD_DRV_H */
3 测试
1）调用接口，并编译项目
LCD_Init(); // 初始化LCD
LCD_Read_ID(); // 读取LCD的驱动芯片ID
2) 运行代码
读取id测试：
清屏测试：
