使用SPI驱动串行LCD的驱动实现(STM32F4)

概述

1. 硬件介绍

1.1 ST7796-LCD

1.2 MCU IO与LCD PIN对应关系

2 功能实现

2.1 使用STM32Cube配置Project

2.2 STM32Cube生成工程

3 代码实现

3.1 SPI接口实现

3.2 LCD驱动程序实现

3.3 测试程序实现

4 测试

源代码下载地址：

https://gitee.com/mftang/stm32_open_test_proj/tree/master/stm32_f407_lcd_proj/UserCode/lcd_drv

测试视频：

使用SPI驱动串行LCD的驱动实现(STM32F4)

概述

本文主要讲述使用STM32硬件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 功能实现

2.1 使用STM32Cube配置Project

1) 配置SPI接口

SPI的参数

2）配置LCD的控制引脚

3）使能外部晶振

2.2 STM32Cube生成工程

使用STM32Cube生成工程，并创建两个目录

User/lcd_drv 驱动文件目录

User/test 测试文件目录

3 代码实现

3.1 SPI接口实现

在spi.c文件中实现读写接口函数，具体实现如下：

/* USER CODE BEGIN 1 */void hal_spi_writebyte( uint8_t byte )
{uint8_t buff[1];buff[0] = byte;HAL_SPI_Transmit( &hspi3, buff, 1, 1000);
}uint8_t hal_spi_readbyte(void)
{uint8_t buff[1];buff[0] = 0xff;return HAL_SPI_Receive( &hspi3, buff, 1, 1000);
}/* USER CODE END 1 */

3.2 LCD驱动程序实现

创建lcd_drv.c实现驱动程序，lcd_spi.c实现和MCU之间的驱动接口

1）lcd_drv.c 程序实现

#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);Lcd_WriteData_16Bit(color); 
}uint16_t LCD_ReadPoint(uint16_t x,uint16_t y)
{uint16_t color;LCD_SetCursor(x,y);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();
} 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 ControlLCD_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 ControlLCD_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();          //LCD//*************3.5 ST7796S IPSLCD_WR_REG(0x11);     lcd_delay_us(120);    //Delay 120mslcd_delay_us(120);    //Delay 120msLCD_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 ControlLCD_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  //00LCD_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);LCD_Clear(DARKBLUE);
}/* End of this file */

2）lcd_spi.c 程序实现

#include "lcd_spi.h"#if !IO_SPI
#include "spi.h"
#endifvoid lcd_gpio_init(void)
{
#if IO_SPIGPIO_InitTypeDef GPIO_InitStruct = {0};/* GPIO Ports Clock Enable */__HAL_RCC_GPIOB_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(LCD_GPIO_PORT, lcd_sck_Pin|lcd_mosi_Pin|lcd_cs_Pin|lcd_rs_Pin|lcd_rst_Pin, GPIO_PIN_RESET);/*Configure GPIO pins : PBPin PBPin PBPin PBPinPBPin */GPIO_InitStruct.Pin = lcd_sck_Pin|lcd_mosi_Pin|lcd_cs_Pin|lcd_rs_Pin|lcd_rst_Pin;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;HAL_GPIO_Init(LCD_GPIO_PORT, &GPIO_InitStruct);/*Configure GPIO pin : PtPin */GPIO_InitStruct.Pin = lcd_miso_Pin;GPIO_InitStruct.Mode = GPIO_MODE_INPUT;GPIO_InitStruct.Pull = GPIO_NOPULL;HAL_GPIO_Init(lcd_miso_GPIO_Port, &GPIO_InitStruct);
#endif}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)
{
#if IO_SPIuint8_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;}
#elsehal_spi_writebyte( Byte );
#endif
} uint8_t SPI_ReadByte(void)
{
#if IO_SPIuint8_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;
#elsereturn hal_spi_readbyte();
#endif
}

3.3 测试程序实现

创建lcd_test.c文件，编写测试程序

4 测试

在如下文件中调用测试程序，其主要实现每隔1s时间刷新屏幕的颜色。

详细代码：

void StartDefaultTask(void *argument)
{/* USER CODE BEGIN StartDefaultTask */int count;LCD_Init();LCD_Read_ID();/* Infinite loop */for(;;){osDelay(1);if(count%1000 == 0){lcd_test();}count++;}/* USER CODE END StartDefaultTask */
}

运行结果如下：