简介
U8g2 还包括 U8x8 库。U8g2 和 U8x8 的功能包括：
- U8g2
包括所有图形程序（线/框/圆画）
支持很丰富的字体库
需要微控制器中的一些内存来渲染显示屏（需要消耗较多的ram空间资源） - U8x8
仅文本输出（字符）设备
仅允许使用每个字符固定大小（8x8 像素）的字体
直接写到显示屏上，无需微控制器中的缓冲（需要消耗较少的ram空间资源）
- U8g2
像素点点阵
OLED其实就是一个M x n 的像素点阵，想显示什么就得把具体位置的像素点亮起来。对于每一个像素点，有可能是1点亮，也有可能是0点亮
坐标系
在坐标系中，左上角是原点，向右是X轴正方向，向下是Y轴正方向。
回调函数
这里只有使用IIC驱动OLED的代码示例
软件IIC
//延时和GPIO初始化 回调函数
uint8_t u8x8_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr){
switch(msg)
{
case U8X8_MSG_GPIO_AND_DELAY_INIT: // called once during init phase of u8g2/u8x8
delay_init();//初始化延时函数
IIC_Init();//软件IIC的IO初始化
break; // can be used to setup pins
case U8X8_MSG_DELAY_NANO: // delay arg_int * 1 nano second
break;
case U8X8_MSG_DELAY_100NANO: // delay arg_int * 100 nano seconds
__NOP();
break;
case U8X8_MSG_DELAY_10MICRO: // delay arg_int * 10 micro seconds
delay_us(10*arg_int);
break;
case U8X8_MSG_DELAY_MILLI: // delay arg_int * 1 milli second
delay_ms(1*arg_int);
break;
case U8X8_MSG_DELAY_I2C: // arg_int is the I2C speed in 100KHz, e.g. 4 = 400 KHz
delay_us(5*arg_int);
break; // arg_int=1: delay by 5us, arg_int = 4: delay by 1.25us
case U8X8_MSG_GPIO_D0: // D0 or SPI clock pin: Output level in arg_int
//case U8X8_MSG_GPIO_SPI_CLOCK:
break;
case U8X8_MSG_GPIO_D1: // D1 or SPI data pin: Output level in arg_int
//case U8X8_MSG_GPIO_SPI_DATA:
break;
case U8X8_MSG_GPIO_D2: // D2 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_D3: // D3 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_D4: // D4 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_D5: // D5 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_D6: // D6 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_D7: // D7 pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_E: // E/WR pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_CS: // CS (chip select) pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_DC: // DC (data/cmd, A0, register select) pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_RESET: // Reset pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_CS1: // CS1 (chip select) pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_CS2: // CS2 (chip select) pin: Output level in arg_int
break;
case U8X8_MSG_GPIO_I2C_CLOCK: // arg_int=0: Output low at I2C clock pin
PBout(8) = arg_int;
break; // arg_int=1: Input dir with pullup high for I2C clock pin
case U8X8_MSG_GPIO_I2C_DATA: // arg_int=0: Output low at I2C data pin
PBout(9) = arg_int;
break; // arg_int=1: Input dir with pullup high for I2C data pin
case U8X8_MSG_GPIO_MENU_SELECT:
u8x8_SetGPIOResult(u8x8, /* get menu select pin state */ 0);
break;
case U8X8_MSG_GPIO_MENU_NEXT:
u8x8_SetGPIOResult(u8x8, /* get menu next pin state */ 0);
break;
case U8X8_MSG_GPIO_MENU_PREV:
u8x8_SetGPIOResult(u8x8, /* get menu prev pin state */ 0);
break;
case U8X8_MSG_GPIO_MENU_HOME:
u8x8_SetGPIOResult(u8x8, /* get menu home pin state */ 0);
break;
default:
u8x8_SetGPIOResult(u8x8, 1); // default return value
break;
}
return 1;
}
//测试主程序
int main(void) {
//初始化u8g2
u8g2_t u8g2; // a structure which will contain all the data for one display
u8g2_Setup_ssd1306_i2c_128x64_noname_f(&u8g2, U8G2_R0, u8x8_byte_sw_i2c, u8x8_gpio_and_delay);// init u8g2 structure
u8g2_InitDisplay(&u8g2); // send init sequence to the display, display is in sleep mode after this,
u8g2_SetPowerSave(&u8g2, 0); // wake up display
while (1){
/* Begin of U8G2*/
static int x = 30,y = 10;
u8g2_ClearBuffer(&u8g2);
u8g2_SetFont(&u8g2, u8g2_font_10x20_mf);
u8g2_DrawStr(&u8g2, x,y,"Data");
if(x >= 70)
{
x = y = 0;
}
else
{
x++;
y++;
}
u8g2_SendBuffer(&u8g2);
/* End of U8G2 */
}
}
硬件IIC
下面代码适用于stm32f1系列的引脚IIC
//为u8g2提供IIC的API接口的函数
uint8_t u8x8_byte_hw_i2c(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
static uint8_t buffer[32]; /* u8g2/u8x8 will never send more than 32 bytes between START_TRANSFER and END_TRANSFER */
static uint8_t buf_idx;
uint8_t *data;
u8 i;
switch(msg){
case U8X8_MSG_BYTE_INIT:
//Init the IIC GPIO
IIC_Init();
break;
case U8X8_MSG_BYTE_START_TRANSFER:
//clear the index
buf_idx = 0;
break;
case U8X8_MSG_BYTE_SEND:
data = (uint8_t *)arg_ptr;
while( arg_int > 0 ){
buffer[buf_idx++] = *data;
data++;
arg_int--;
}
break;
case U8X8_MSG_BYTE_END_TRANSFER:
IIC_Start();
IIC_Send_Address_Write(0x78);//write your oled address in here
for(i = 0; i < buf_idx; i++){
IIC_Send_Byte(buffer[i]);
}
IIC_Stop();
break;
case U8X8_MSG_BYTE_SET_DC:
/* ignored for i2c */
break;
default:
return 0;
}
return 1;
}
//为u8g2提供延时函数接口的函数
uint8_t u8x8_gpio_and_delay(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
switch(msg){
case U8X8_MSG_GPIO_AND_DELAY_INIT:
delay_init(); //延时函数初始化
break;
case U8X8_MSG_DELAY_MILLI:
delay_ms(arg_int);
break;
case U8X8_MSG_GPIO_I2C_CLOCK:
break;
case U8X8_MSG_GPIO_I2C_DATA:
break;
default:
return 0;
}
return 1; // command processed successfully.
}
//测试主程序
void TestIO_Init(void){
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能端口时钟
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //端口配置
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD; //下拉输入
GPIO_Init(GPIOA, &GPIO_InitStructure); //根据设定参数初始化
}
int main(void){
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //设置系统中断优先级分为2
u8g2_t u8g2; // a structure which will contain all the data for one display
u8g2_Setup_ssd1306_i2c_128x64_noname_f(&u8g2, U8G2_R0, u8x8_byte_hw_i2c, u8x8_gpio_and_delay);// init u8g2 structure
u8g2_InitDisplay(&u8g2); // send init sequence to the display, display is in sleep mode after this,
u8g2_SetPowerSave(&u8g2, 0); // wake up display
while (1){
/* Begin of U8G2*/
static int x = 30,y = 10;
u8g2_ClearBuffer(&u8g2);
u8g2_SetFont(&u8g2, u8g2_font_10x20_mf);
u8g2_DrawStr(&u8g2, x,y,"Data");
if(x >= 70)
{
x = y = 0;
}
else
{
x++;
y++;
}
u8g2_SendBuffer(&u8g2);
/* End of U8G2 */
}
}
