【51单片机快速入门指南】6.2：SPI 、八线、四线控制 LCD12864 屏幕及Proteus的仿真（支持中文汉字）
目录
- 硬知识
-
- LCD12864简介
-
- 主控芯片ST7920的功能是：
- 驱动芯片ST7921的功能是：
- 引脚功能
- 时序
-
- 并行通信
- 串行通信
- 指令
- 存储结构
- 操作
- 取模软件的配置
- 示例程序
-
- st7920.c
- st7920.h
- 测试程序
-
- 显示图片
-
- 图片1
-
- 实验现象
- 图片2
-
- 实验现象
- 显示字符
-
- 英文
-
- 实验现象
- 中文
-
- 实验现象
- Proteus的仿真
普中51-单核-A2
STC89C52
Windows 10 20H2
Proteus 8 Frofessional v8.9 SP2
Keil uVision V5.29.0.0
PK51 Prof.Developers Kit Version:9.60.0.0
移植自发布一个ST7920的LCD12864 Proteus仿真模型,支持串口和4bit模式通讯 —— cdhigh
参考资料：《LCD12864液晶显示模块数据手册（带字库）》
硬知识
LCD12864简介
LCD12864液晶屏，背面3个COB牛屎堆，一个主控芯片ST7920，另外两个是移位芯片ST7921.
主控芯片ST7920的功能是：
- 与我们的单片机并行通信。
- 字库ROM、CGROM，DDRAM等。
- 行扫描COM0 ~ COM31…
- 列扫描SEG0 ~ SEG63…
- 串行方式发送数据到两片ST7921驱动芯片。
驱动芯片ST7921的功能是：
- 接收来自ST7920的串行信号，转化成并口驱动电压。
- 根据信号要求，两片芯片分别驱动SEG64~ SEG159，SEG160~ SEG255
LCD12864它本质上是256x32点的矩阵屏，32行扫描是COM0-COM31，列字节是SEG0-SEG255总共32字节，每个字节8bit，总共256位。.
原本左右拼接的256x32点，变成了上下拼接的128x64点。如下图所示：
引脚功能
时序
并行通信
串行通信
指令
存储结构
操作
uint8_t code LCD12864_Write_CGRAM[]=
{
0x60,0x00,0x91,0xF4,0x96,0x0C,0x6C,0x04,
0x08,0x04,0x18,0x00,0x18,0x00,0x18,0x00,
0x18,0x00,0x18,0x00,0x18,0x00,0x08,0x00,
0x0C,0x04,0x06,0x08,0x01,0xF0,0x00,0x00
};//温度符号的 32 个字节字模
取模软件的配置
示例程序
VSS —— GND
VDD —— VCC(5V or 3.3V)
V0 亮度调节
CS(RS) —— 接VCC，持续高电平，一直选通。
MOSI(R/W)—— 接MOSI
SCLK(E) —— 接SCLK
PSB —— 接GND 串行模式
BLA —— VCC(5V or 3.3V)
BLK —— 接GND
剩余引脚不接，留空
stdint.h见【51单片机快速入门指南】1：基础知识和工程创建
软件SPI程序见【51单片机快速入门指南】5：软件SPI
SPI选择模式3。
根据电路修改Software_SPI.h
模式选择在st7920.h内
st7920.c
//ST7920 LCD 驱动
#include "st7920.h"
#include "./Software_SPI/Software_SPI.h"
void delay_ms(int i);
void st7920_delay()
{
}
void LCD12864_CS_H() //若SPI总线上只有屏幕，则可接VCC
{
LCD12864_CS = 1;
}
void LCD12864_CS_L()
{
LCD12864_CS = 0;
}
void LCD12864_PSB_L() //接GND或给低电平以实现SPI通讯
{
LCD12864_PSB = 0;
}
void LCD12864_RS_H()
{
RS_Pin = 1;
}
void LCD12864_RS_L()
{
RS_Pin = 0;
}
void LCD12864_WR_H()
{
WR_Pin = 1;
}
void LCD12864_WR_L()
{
WR_Pin = 0;
}
void LCD12864_EN_H()
{
EN_Pin = 1;
}
void LCD12864_EN_L()
{
EN_Pin = 0;
}
uint8_t LCD12864_Port_Read()
{
return LCD12864_Port;
}
//并口模式下写八位
void LCD12864_Port_Write_8B(uint8_t Data)
{
LCD12864_Port = Data;
}
//4位模式下写半个字节（高4位）
void LCD12864_Port_Write_4B(uint8_t Data)
{
LCD12864_Port &= 0x0F;
LCD12864_Port |= Data;
}
//初始化
void LCD_init(void)
{
#if LCD_INTERFACE == MODE_SPI
LCD12864_PSB_L();
#endif
delay_ms(50);
LCD_write_command(0x33);
delay_ms(1);
LCD_write_command(0x32);
delay_ms(1);
#if LCD_INTERFACE == MODE_4BIT
LCD_write_command(0x28);
delay_ms(1);
LCD_write_command(0x28);
delay_ms(1);
#endif
LCD_write_command(0x08); //显示关
delay_ms(1); //大于100uS的延时程序
LCD_write_command(0x10); //光标设置
delay_ms(1); //大于100uS的延时程序
LCD_write_command(0x0C); //显示开
delay_ms(1); //大于100uS的延时程序
LCD_write_command(0x01); //Display Clear
delay_ms(10); //大于10mS的延时程序
LCD_write_command(0x06); //光标从右向左加1位移动
delay_ms(10); //大于10mS的延时程序
}
//写命令
void LCD_write_command(unsigned char command)
{
#if LCD_INTERFACE == MODE_SPI
LCD2_spi_write_byte(0xf8);
st7920_delay();
LCD2_spi_write_byte_standard(command);
#else
LCD12864_RS_L(); //RS=0
LCD_write_byte(command);
delay_ms(1);
#endif
}
//写数据
void LCD_write_data(unsigned char Data)
{
#if LCD_INTERFACE == MODE_SPI
LCD2_spi_write_byte(0xfa);
st7920_delay();
LCD2_spi_write_byte_standard(Data);
#else
LCD12864_RS_H(); //RS=1
LCD_write_byte(Data);
#endif
}
//并口模式写一个字节到控制器
void LCD_write_byte(unsigned char Data)
{
#if LCD_INTERFACE == MODE_4BIT
LCD_write_half_byte(Data);
Data <<= 4;
LCD_write_half_byte(Data);
#else
LCD12864_Port_Write_8B(Data);
LCD12864_WR_L();
LCD12864_EN_H(); //EN端产生一个由低电平变高电平，写LCD
st7920_delay();
LCD12864_EN_L(); //EN端产生一个由高电平变低电平，写LCD
st7920_delay();
LCD12864_WR_H();
#endif
}
//4位模式下写半个字节（高4位）
void LCD_write_half_byte(unsigned char half_byte)
{
LCD12864_Port_Write_4B(half_byte);
LCD12864_WR_L();
LCD12864_EN_H(); //EN端产生一个由低电平变高电平，写LCD
st7920_delay();
LCD12864_EN_L(); //EN端产生一个由高电平变低电平，写LCD
st7920_delay();
LCD12864_WR_H();
}
//串行模式下写一个字节
void LCD2_spi_write_byte(unsigned char Data)
{
LCD12864_CS_H();
SOFT_SPI_RW_MODE3(Data);
LCD12864_CS_L();
}
//标准处理，一个字节要拆成两个字节发送
void LCD2_spi_write_byte_standard(unsigned char Data)
{
LCD2_spi_write_byte(Data & 0xf0);
LCD2_spi_write_byte((Data << 4) & 0xf0);
}
//并口模式下读数据
unsigned char LCD_read_data(void)
{
unsigned char Data;
LCD12864_RS_H();
Data = LCD_read_byte();
#if LCD_INTERFACE == MODE_4BIT
Data = (Data & 0xf0) | ((LCD_read_byte() >> 4) & 0x0f);
#endif
return Data;
}
//并口模式下读状态
unsigned char LCD_read_status(void)
{
unsigned char Data;
LCD12864_RS_L();
Data = LCD_read_byte();
#if LCD_INTERFACE == MODE_4BIT
Data = (Data & 0xf0) | ((LCD_read_byte() >> 4) & 0x0f);
#endif
return Data;
}
//并口模式下读一个字节，如果是4bit模式，则只有高4位是有效的
unsigned char LCD_read_byte(void)
{
unsigned char Data;
LCD12864_WR_H();
LCD12864_EN_L(); //EN端产生上升沿，ST7920开始输出数据
st7920_delay();
LCD12864_EN_H();
st7920_delay();
Data = LCD12864_Port_Read();
LCD12864_EN_L();
return Data;
}
//设置字符模式的地址
//第一行首地址：0x80
//第二行首地址：0x80+0x10 (0x90)
//第三行首地址：0x80+0x08 (0x88)
//第四行首地址：0x80+0x10+0x08 (0x98)
void LCD_set_text_address(unsigned int rowCol)
{
unsigned char start = 0x80;
unsigned char row = (rowCol >> 8) & 0xff;
unsigned char col = rowCol & 0xff;
if (row == 1) {
start = 0x90;
}
if (row == 2) {
start = 0x88;
}
if (row == 3) {
start = 0x98;
}
LCD_write_command(start + col);
}
//将字符模式的行列号转换为内部的XY坐标，返回的高字节为X，低字节为Y
//row (HIGH_BYTE(rowCol)): 行号，0-3
//col (LOW_BYTE(rowCol)): 列号，0-7
unsigned int LCD_rowCol_to_inter_Xy(unsigned int rowCol)
{
unsigned char row = (rowCol >> 8) & 0x03;
unsigned char col = rowCol & 0x07;
unsigned char x = col + 8 * (unsigned char)(row / 2);
unsigned char y = (row * 16) & 0x1f;
return (x << 8) | y;
}
//设置绘图模式的地址
//x: 0-127 (注意x必须为16的整数倍)
//y:0-63
void LCD_set_graphic_address(unsigned char x, unsigned char y)
{
unsigned char xWord, downPage, yInter;
x &= 0x7f;
y &= 0x3f;
xWord = x / 16; //内部X地址，一个地址管16位
downPage = y / 32; //0:上半屏 1:下半屏
yInter = y & 0x1f; //内部Y坐标
LCD_write_command(0x80 + yInter); //先设置Y地址
LCD_write_command(0x80 + xWord + 8 * downPage);
}
//显示清屏函数
void LCD_clear(void)
{
unsigned char x, y;
LCD_write_command(0x08); //避免清屏过程中闪烁，先关显示
st7920_delay();
LCD_write_command(0x01); //清DDRAM
//清GDRAM,12864仅用了一半的GDRAM，清一半即可
//如果没有使用到绘图GDRAM，也可以不清GDRAM，省点时间和代码空间
LCD_startGraphic();
for (y = 0; y < 32; y++)
{
LCD_write_command(0x80 + y); //y
LCD_write_command(0x80 + 0); //x
for (x = 0; x < 16; x++)
{
LCD_write_data(0x00);
LCD_write_data(0x00);
}
}
LCD_endGraphic();
LCD_write_command(0x0C); //显示开
delay_ms(10);
}
//开启扩展命令的绘图指令
void LCD_startGraphic(void)
{
#if LCD_INTERFACE == MODE_4BIT
LCD_write_command(0x24); //扩展指令集
LCD_write_command(0x26); //绘图命令开启
#else
LCD_write_command(0x34); //扩展指令集
LCD_write_command(0x36); //绘图命令开启
#endif
}
//结束扩展命令的绘图指令(可选)
void LCD_endGraphic(void)
{
#if LCD_INTERFACE == MODE_4BIT
LCD_write_command(0x26); //绘图命令关闭
LCD_write_command(0x20); //回到基本指令
#else
LCD_write_command(0x36); //绘图命令关闭
LCD_write_command(0x30); //回到基本指令
#endif
}
//反白或取消反白对应16X16区域，一般用于菜单选择
//row (HIGH_BYTE(rowCol)): 行号，0-3
//col (LOW_BYTE(rowCol)): 列号，0-7
//charNum: 要反白的字符数量，注意不要超过行末
//ST7920内置的反白作用不大，它只能整行反白，而且反白第一行，第三行也会一起反白
//所以此函数使用另外的方法实现：绘图区对应的位全部写0xff，异或后即可反白
void LCD_Inverse_16X16(unsigned int rowCol, unsigned char charNum, unsigned char reverse)
{
unsigned char i, ch;
unsigned int xy = LCD_rowCol_to_inter_Xy(rowCol);
unsigned char x = (xy >> 8) & 0xff;
unsigned char y = xy & 0x3f;
LCD_startGraphic();
for (i = 0; i < 16; i++) //把对应字符的GDRAM全部写成0xff，异或后就是反白
{
LCD_write_command(0x80 + y + i); //先写垂直地址y
LCD_write_command(0x80 + x); //x
for (ch = 0; ch < charNum; ch++)
{
LCD_write_data(reverse ? 0xff : 0x00);
LCD_write_data(reverse ? 0xff : 0x00);
}
}
LCD_endGraphic();
}
//显示一个字符，12864可以显示4行，每行8个汉字或每行16个字母
//col: 列号，0-15
//row: 行号，0-3
//字符编码：小于0x80的为ASCII，否则为汉字，汉字编码高字节在左边
void LCD_write_char(unsigned int rowCol, unsigned int Code)
{
unsigned char high = (Code >> 8) & 0xff;
unsigned char low = Code & 0xff;
LCD_set_text_address(rowCol);
if (Code > 0x80)
{
LCD_write_data(high);
}
LCD_write_data(low);
}
//显示一个字符串，注意不要超过一行的长度（8个汉字或16个字母）
//rowCol: 左8位为行(0-3)，右8位为列(0-15)
void LCD_write_string(unsigned int rowCol, const char * p)
{
LCD_set_text_address(rowCol);
while (*p != 0)
{
LCD_write_data(*p);
p++;
}
}
void LCD_Draw_Bmp(unsigned char *pImage, unsigned char col, unsigned char row, unsigned char x0, unsigned char y0)
{
unsigned char i, y;
LCD_startGraphic();
for (y = y0; y < row + y0; y++)
{
LCD_set_graphic_address(x0, y);
for (i = 0; i < col/8; i++)
{
LCD_write_data(*pImage);
pImage++;
}
}
LCD_endGraphic();
}
//只有并行接口能读ST7920，如果串行接口需要打点，则需要开辟RAM缓冲区
#if LCD_INTERFACE != MODE_SPI
//在对应X/Y位置显示一个点
void LCD_write_dot(unsigned char x, unsigned char y)
{
unsigned char xBit, high, low;
xBit = x & 0x0f;
LCD_startGraphic();
LCD_set_graphic_address(x, y);
LCD_read_data(); //根据手册，设置完地址后的第一次读操作返回的数据无效
high = LCD_read_data();
low = LCD_read_data();
//回写
LCD_set_graphic_address(x, y);
if (xBit < 8) //低8位
{
LCD_write_data(high | (0x01 << (7 - xBit)));
LCD_write_data(low);
}
else
{
LCD_write_data(high);
LCD_write_data(low | (0x01 << (15 - xBit)));
}
LCD_endGraphic();
}
#endif
st7920.h
//ST7920 LCD 驱动
//Author: cdhigh <2021-09-22>
//ST7920的绘图结构：左上角为坐标原点，写入的字节表示从某个坐标开始的8个横向像素，
//每行 128/8=16 个字节，每个字节左边为最低位，右边为最高位，纵向64行。
//DDRAM地址
//0x80 0x81 0x82 0x83 0x84 0x85 0x86 0x87 //第一行汉字位置
//0x90 0x91 0x92 0x93 0x94 0x95 0x96 0x97 //第二行汉字位置
//0x88 0x89 0x8a 0x8b 0x8c 0x8d 0x8e 0x8f //第三行汉字位置
//0x98 0x99 0x9a 0x9b 0x9c 0x9d 0x9e 0x9f //第四行汉字位置
#ifndef __ST7290_H_
#define __ST7290_H_
#include 测试程序
显示图片
图片1
#include 实验现象
图片打印较慢，请耐心等待。
图片2
//liberty.bmp
//48x64
code unsigned char bmpData[] =
{
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x00,0x00,0x00,0x00,0x01,0xE0,0x00,
0x00,0x00,0x00,0x01,0x20,0x00,0x00,0x00,0x00,0x03,0xE0,0x00,0x00,0x00,0x00,0x03,
0xF0,0x00,0x00,0x00,0x00,0x01,0xE0,0x00,0x00,0x00,0x00,0x01,0xC0,0x00,0x00,0x00,
0x00,0x01,0xE0,0x00,0x00,0x00,0x00,0x01,0xE1,0x80,0x00,0x00,0x00,0x01,0xF1,0x84,
0x00,0x00,0x00,0x01,0xF9,0x9C,0x00,0x00,0x00,0x00,0xFF,0xB8,0x00,0x00,0x00,0x00,
0xBF,0xFF,0x00,0x00,0x00,0x00,0xFF,0xFF,0x00,0x00,0x00,0x00,0xDF,0xFC,0x00,0x00,
0x00,0x00,0xDF,0xFF,0x80,0x00,0x00,0x00,0xDC,0x7F,0x00,0x00,0x00,0x00,0xDE,0xFC,
0x00,0x00,0x00,0x00,0xDC,0xF0,0x00,0x00,0x00,0x01,0xFF,0x70,0x00,0x00,0x00,0x01,
0xE7,0xD8,0x00,0x00,0x00,0x01,0xB3,0xD8,0x00,0x00,0x00,0x00,0xE1,0xF0,0x00,0x00,
0x00,0x00,0xC1,0xF8,0x00,0x00,0x00,0x00,0x47,0xB8,0x00,0x00,0x00,0x00,0x4F,0xBC,
0x00,0x00,0x00,0x00,0x4B,0x1D,0xC0,0x00,0x00,0x00,0x7A,0x7F,0xE0,0x00,0x00,0x00,
0x36,0x6E,0x70,0x00,0x00,0x00,0x6C,0x6C,0xE0,0x00,0x00,0x00,0x6C,0x4C,0xE0,0x00,
0x00,0x00,0xD8,0xCC,0xC0,0x00,0x00,0x00,0xD8,0xC5,0xC0,0x00,0x00,0x00,0x70,0xC7,
0xC0,0x00,0x00,0x00,0x3C,0xC7,0x80,0x00,0x00,0x00,0x38,0xC7,0x80,0x00,0x00,0x00,
0x78,0xC7,0x00,0x00,0x00,0x00,0x70,0xC6,0x00,0x00,0x00,0x00,0x70,0xC6,0x00,0x00,
0x00,0x00,0x70,0xC6,0x00,0x00,0x00,0x00,0x30,0xC2,0x00,0x00,0x00,0x00,0x20,0xC2,
0x00,0x00,0x00,0x00,0x60,0xC2,0x00,0x00,0x00,0x00,0x60,0xC6,0x00,0x00,0x00,0x00,
0x60,0xFE,0x00,0x00,0x00,0x00,0x60,0xFE,0x00,0x00,0x00,0x00,0x60,0x7E,0x00,0x00,
0x00,0x00,0x60,0x7E,0x00,0x00,0x00,0x00,0x60,0xFE,0x00,0x00,0x00,0x00,0x63,0xFE,
0x00,0x00,0x00,0x00,0x67,0x7E,0x00,0x00,0x00,0x00,0x7F,0xFE,0x00,0x00,0x00,0x00,
0x7F,0xFE,0x00,0x00,0x00,0x00,0x7F,0xDF,0x00,0x00,0x00,0x00,0x5F,0xDF,0x00,0x00,
0x00,0x01,0xFF,0xFF,0x00,0x00,0x00,0x01,0x80,0x01,0x00,0x00,0x00,0x07,0xFF,0xFF,
0xC0,0x00,0x00,0x06,0xFF,0xFE,0xE0,0x00,0x00,0x04,0x00,0x00,0x60,0x00,0x00,0x07,
0xFF,0xFF,0xE0,0x00,0x00,0x07,0xFF,0xFF,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
void main(void)
{
LCD_init();
LCD_clear();
LCD_Draw_Bmp(bmpData, 48, 64, 32, 0);
while(1)
{
}
}
实验现象
显示字符
英文
void main(void)
{
LCD_init();
LCD_clear();
LCD_write_string(0x0000, "0123456789abcdef");
LCD_write_string(0x0100, "~`!@#$%^&*()_-+=");
LCD_write_string(0x0200, "ABCDEFGHIJKLMNOP");
LCD_write_string(0x0300, "QRSTUVWXYZ");
while(1)
{
}
}
实验现象
中文
void main(void)
{
LCD_init();
LCD_clear();
LCD_write_string(0x0000, "祥瑞不在凤凰麒麟");
LCD_write_string(0x0100, "太平须得边将忠臣");
LCD_write_string(0x0200, "仁得百僚师长肝胆");
LCD_write_string(0x0300, "不用三\xfd军罗绮金银");
while(1)
{
}
}
实验现象
Proteus的仿真
需添加LCD12864的模型：发布一个ST7920的LCD12864 Proteus仿真模型,支持串口和4bit模式通讯 —— cdhigh
下载后将LIBRARY、MODELS文件夹与Proteus安装目录下DATA文件夹内的同名文件夹合并
