树莓派 -- oled 续（1） wiringPi

在上文中，分析了wiringPi 的oled demo是使用devfs来控制spi master和spi slave通讯。

https://blog.csdn.net/feiwatson/article/details/81149028

再详细分析一下demo的OLED SSD1306相关代码。

定义一个buffer

unsigned char buffer[1024];

初始化

void SSD1306_begin()

{

    pinMode(RST,OUTPUT); //Pin24 设置为输出

    pinMode(DC,OUTPUT);  //Pin27 设置为输出

    wiringPiSPISetup(channel,2000000);    //2M

    digitalWrite(RST,HIGH);   //reset

    delay(10);

    digitalWrite(RST,LOW);

    delay(10);

    digitalWrite(RST,HIGH);

    command(SSD1306_DISPLAYOFF);

    command(SSD1306_SETDISPLAYCLOCKDIV);

    command(0x80);                              // the suggested ratio 0x80

    command(SSD1306_SETMULTIPLEX);

    command(0x3F);

    command(SSD1306_SETDISPLAYOFFSET);

    command(0x0);                               // no offset

    command(SSD1306_SETSTARTLINE | 0x0);        // line #0

    command(SSD1306_CHARGEPUMP);

    command((vccstate == SSD1306_EXTERNALVCC) ? 0x10 : 0x14);

    command(SSD1306_MEMORYMODE);

    command(0x00);                              // 0x0 act like ks0108

    command(SSD1306_SEGREMAP | 0x1);

    command(SSD1306_COMSCANDEC);

    command(SSD1306_SETCOMPINS);

    command(0x12);           // TODO - calculate based on _rawHieght ?

    command(SSD1306_SETCONTRAST);

    command((vccstate == SSD1306_EXTERNALVCC) ? 0x9F : 0xCF);

    command(SSD1306_SETPRECHARGE);

    command((vccstate == SSD1306_EXTERNALVCC) ? 0x22 : 0xF1);

    command(SSD1306_SETVCOMDETECT);

    command(0x40);

    command(SSD1306_DISPLAYALLON_RESUME);

    command(SSD1306_NORMALDISPLAY);

    command(SSD1306_DISPLAYON);

}

设置一个pixel对应的buffer中的bit. 一列8个pixel对应一个buffer字节

void SSD1306_pixel(int x,int y,char color)

{

    if(x > width || y > height)return ;

    if(color)

        buffer[x+(y/8)*width] |= 1<<(y%8);

    else

        buffer[x+(y/8)*width] &= ~(1<<(y%8));

}

其他的SSD1306_bitmap , SSD1306_string, SSD1306_char3216, SSD1306_char1616等函数通过调用SSD1306_pixel设置buffer

将buffer中缓冲的图像显示

void SSD1306_display()

{

    command(SSD1306_COLUMNADDR);

    command(0);         //cloumn start address

    command(width -1); //cloumn end address

    command(SSD1306_PAGEADDR);

    command(0);         //page atart address

    command(pages -1); //page end address

    digitalWrite(DC,HIGH);

    wiringPiSPIDataRW(channel,buffer,sizeof(buffer));

}

图片中显示图像的代码如下

int main(int argc,char **argv)

{

    time_t now;

    struct tm *timenow;

    if(wiringPiSetup() < 0)return 1;

    printf("OLED Test Program !!!\n");

    SSD1306_begin();

    SSD1306_bitmap(0,0,waveshare,128,64);

    SSD1306_display();

    delay(2000);

    SSD1306_clear();

    while(1)

    {

        time(&now);

        timenow = localtime(&now);

        SSD1306_bitmap(0, 2, Singal816, 16, 8);

        SSD1306_bitmap(24, 2,Bluetooth88, 8, 8);

        SSD1306_bitmap(40, 2, Msg816, 16, 8);

        SSD1306_bitmap(64, 2, GPRS88, 8, 8);

        SSD1306_bitmap(90, 2, Alarm88, 8, 8);

        SSD1306_bitmap(112, 2, Bat816, 16, 8); 

        SSD1306_string(0, 52, "MUSIC", 12, 0);

        SSD1306_string(52, 52, "MENU", 12, 0);

        SSD1306_string(98, 52, "PHONE", 12, 0);

        SSD1306_char3216(0,16, value[timenow->tm_hour/10]);

        SSD1306_char3216(16,16, value[timenow->tm_hour%10]);

        SSD1306_char3216(32,16, ':');

        SSD1306_char3216(48,16, value[timenow->tm_min/10]);

        SSD1306_char3216(64,16, value[timenow->tm_min%10]);

        SSD1306_char3216(80,16, ':');

        SSD1306_char3216(96,16, value[timenow->tm_sec/10]);

        SSD1306_char3216(112,16, value[timenow->tm_sec%10]);

        SSD1306_display();

    }

    return 0;

}

巴特西

树莓派 -- oled 续（1） wiringPi

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