原理

之前没有操作过12864这种类型的屏，但是，操作过其他类型的，原理都是相通的。12864是拥有128x64像素点这类屏幕的称号吧。屏幕有64行，128列；每个汉字是16x16，所以一个这样的屏，最多可以显示4x8的汉字或者8x16的字符。

我使用的是不带字库的I2C接口的屏幕，主芯片是ST7656。这样的屏，只能写，不能读。先配置屏幕，然后通过字模制作软件制作出待显示内容的像素数字，最后，通过数据线传送给屏幕显示。了解了原理后，接下来就根据主芯片的数据手册进行配置屏幕就好了。

硬件连线

CS：片选

RST: 复位

RS：数据或命令选择

SDA：I2C数据线

SCL：I2C时钟线

I2C采用的是软件模拟的

底层写操作

#define IO_ST7565_CS_0   GPIO_WriteBit(GPIOB, GPIO_Pin_5, RESET)

#define IO_ST7565_CS_1   GPIO_WriteBit(GPIOB, GPIO_Pin_5, SET)

#define IO_ST7565_SDA_0 GPIO_WriteBit(GPIOB, GPIO_Pin_1, RESET)  

#define IO_ST7565_SDA_1 GPIO_WriteBit(GPIOB, GPIO_Pin_1, SET)   

#define IO_ST7565_SCK_0 GPIO_WriteBit(GPIOB, GPIO_Pin_2, RESET)  

#define IO_ST7565_SCK_1 GPIO_WriteBit(GPIOB, GPIO_Pin_2, SET)   

#define IO_ST7565_RST_0 GPIO_WriteBit(GPIOB, GPIO_Pin_4, RESET)

#define IO_ST7565_RST_1 GPIO_WriteBit(GPIOB, GPIO_Pin_4, SET)

#define IO_ST7565_RS_0 GPIO_WriteBit(GPIOB, GPIO_Pin_3, RESET)

#define IO_ST7565_RS_1 GPIO_WriteBit(GPIOB, GPIO_Pin_3, SET)

static void io_delay(uint16_t nCount)

{

    while (nCount--);

}

/* rs == 1 data rs==0  cmd */

void ST7565_Write(uint8_t dat,uint8_t rs)  

{

uint8_t i;

IO_ST7565_SCK_0;

IO_ST7565_CS_0;

if(!rs)

{

IO_ST7565_RS_0; //Command

}else{

IO_ST7565_RS_1;

}

io_delay(5);

for(i = 0; i < 8; i++)

{ 

if( dat & 0x80){

IO_ST7565_SDA_1;

}else{

IO_ST7565_SDA_0;

}

dat <<= 1;

IO_ST7565_SCK_1;

io_delay(5);

IO_ST7565_SCK_0;

io_delay(5);

}

io_delay(5);

IO_ST7565_CS_1;

IO_ST7565_RS_1;

io_delay(5);

}

/* write cmd */

void writec(uint8_t com)

{ 

ST7565_Write(com,0);

}

/* write data */

void writed(uint8_t dat)

{  

ST7565_Write(dat,1);

}

初始化

void LcmClear(uint8_t FillData)

{

uint8_t i,j;

for(i=0;i<8;i++)

{

writec(0xB0|i); //Set Page Address

writec(0x10); //Set Column Address = 0

writec(0x00); //Colum from S1 -> S128 auto add

for(j=0;j<132;j++)

{

writed( FillData );

}

}

}

void LcmInit(void)

{

IO_ST7565_CS_1;

IO_ST7565_RST_0;

delay_ms(10); //hard reset for 10ms

IO_ST7565_RST_1;

delay_ms(10); 

writec(0xAE); //Display OFF

writec(0xA2); //1/64 Duty 1/9 Bias

writec(0xA0); //ADC select S0->S131(玻璃设计用S1-S128)

writec(0xC0); //com1 --> com64

writec(0x24); //对某些模块没用,用的外部Rb/Ra

writec(0x81); //Sets V0

writec(48);   //内部电位器调节对比度

writec(0x2F); //voltage follower ON regulator ON booster ON

writec(0xA6); //Normal Display (not reverse dispplay)

writec(0xA4); //Entire Display Disable

writec(0x40); //Set Display Start Line = com0

writec(0xB0); //Set Page Address = 0

writec(0x10); //Set Column Address 4 higher bits = 0

writec(0x00); //Set Column Address 4 lower bits = 1 , from IC SEG1 -> SEG128

LcmClear(0);

writec(0xAF); //Display ON

}

上面的这些命令代表什么含义，输入的命令值具体代表什么，都可以在ST7656的官方数据手册中找到答案。

应用

使用字模软件制作字模：

uint8_t hzk[] = {

    /*--  文字:  请 0 --*/

    /*--  宋体12;  此字体下对应的点阵为：宽x高=16x16   --*/

    0x00,0x00,0xFE,0x04,0x08,0x00,0xFF,0xA8,0xA8,0xA8,0xAA,0xA9,0xFE,0x00,0x00,0x00,

    0x02,0x42,0x33,0x00,0x00,0x22,0x2A,0x2A,0x2A,0xFE,0x2A,0x2A,0x2A,0x22,0x02,0x00,

}

uint8_t num[] = {

    /*--  文字:  0  --*/

    /*--  宋体12;  此字体下对应的点阵为：宽x高=8x16   --*/

    0x00,0x07,0x08,0x10,0x10,0x08,0x07,0x00,0x00,0xF0,0x08,0x04,0x04,0x08,0xF0,0x00,

}

/* page: 0 - 7; col: 0 - 128 */

void show_char(uint8_t page, uint8_t col, uint8_t *data)

{

    uint8_t i;

    /* set page address */

    writec(0xB0 | page);

    /* set column address */

    writec(0x10 | col >> 4);

    writec(col & 0xf);

    for(i = 8; i < 16; i++) {

writed(data[i]);

}

page++;

/* set page address */

    writec(0xB0 | page);

    /* set column address */

    writec((0x10 | (col >> 4)));

    writec(col & 0xf);

for(i = 0; i < 8; i++)

{

writed(data[i]);

}

}

/* page: 0/2/4/6; col: 0 - 128 */

void show_chinese(uint8_t page, uint8_t col, uint8_t *data)

{

    uint8_t i;

    /* set page address */

    writec(0xB0 | page);

    /* set column address */

    writec(0x10 | col >> 4);

    writec(col & 0xf);

    for(i = 0; i < 16; i++) {

writed(data[i]);

}

page++;

/* set page address */

    writec(0xB0 | page);

    /* set column address */

    writec((0x10 | (col >> 4)));

    writec(col & 0xf);

for(i = 16; i < 32; i++)

{

writed(data[i]);

}

}

show_chinese(4, 0x20, hzk);

show_char(2, 0x30, num);