[Arduino技巧] ST7920 LCD也能用u8g2函式庫，連自訂的中文字庫也能用！

st7920-1-1

很多人都受夠了單調又制式的1602 LCD了吧，ST7920提供我們另外一種選擇，大尺寸、128x64高解析度，可以顯示文字及圖形，價格也合理，大家真的可以試試！

之前傑森介紹過ST7920如何使用內建的字庫顯示繁體中文，有興趣的朋友可以去看看。

ST7920內建繁體中文字庫的LCD，Arduino快速上手！

但那個方法雖然快速簡單，但函式庫功能比較陽春，要做華麗麗的畫面就有難度了。這時你就可以考慮改用u8g2函式庫了。雖然無法取用內建的字庫，但你卻可以使用之前已經建好的u8g2中文字庫，而且畫面的組合會變得更加有彈性。

線上購買ST7920 LCD：https://www.jmaker.com.tw/products/st7920-lcd

有關u8g2自訂中文字庫的方法，請參考另一篇：

使用u8g2函式庫建立自訂字庫，讓OLED顯示中文

為了減少接線，傑森建議採用SPI的介面，只要接好3根訊號線，還幾條供電的線就行了！

ST7920_spi

接線方式：

RS >> PIN10
R/W >> PIN11
E >> PIN13

GND >> GND
VCC >> 5V
PSB >> GND //PSB接GND是指啟用SPI
BLA >> 3.3V
BLK >> GND

接好線後就可以開始寫程式了！因為用的是u8g2函式庫，用法根本和OLED一模一樣，所以入門的部份請參考傑森的另一篇文章：

一套u8g2函式庫，玩遍所有OLED

程式我們基本上延用同一支範例，只要修改一行：

U8G2_ST7920_128X64_1_HW_SPI u8g2(U8G2_R0, /* CS=*/ 10, /* reset=*/ U8X8_PIN_NONE);

基本的範例就是這樣：

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

U8G2_ST7920_128X64_1_HW_SPI u8g2(U8G2_R0, /* CS=*/ 10, /* reset=*/ U8X8_PIN_NONE);

#define imgWidth 128
#define imgHeight 48  //這裡只用到48的高度，因為上方要放文字

static const unsigned char PROGMEM logo_bmp[] =
{ 
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void setup(void) {
  u8g2.begin(); 
  //u8g2.setDisplayRotation(U8G2_R2);  //視需求反轉LCD
}

void loop(void) {
  u8g2.setFont(u8g2_font_HelvetiPixelOutline_te); //設定字型
  u8g2.firstPage();
  do {
    u8g2.drawStr(0,13,"Hello World !");  //輸出文字
    u8g2.drawXBMP(0,16, imgWidth, imgHeight, logo_bmp);  //繪圖
  } while ( u8g2.nextPage() );
  //delay(1000);
}

上方會有一行文字，並且用u8g2的字型；下方則是一張圖片，很簡單對吧^^

st7920-1

但又有問題了，這個LCD原本是有內建中文的(繁體或簡體)，這時我們想要顯示中文怎麼辨？！如同本文一開始介紹的，如果要顯示中文，就用u8g2自訂字庫的方法啊！

有關u8g2自訂中文字庫的方法，請參考另一篇：

使用u8g2函式庫建立自訂字庫，讓OLED顯示中文

以下的範例就是假設大家已經建立好自己的字庫了，再進行改寫的範例：

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif
U8G2_ST7920_128X64_1_HW_SPI u8g2(U8G2_R0, /* CS=*/ 10, /* reset=*/ U8X8_PIN_NONE);

void setup(void) {
  u8g2.begin();
  //u8g2.setDisplayRotation(U8G2_R2);  //視需求反轉LCD
  u8g2.enableUTF8Print();  //啟用UTF8文字的功能  
}

void loop(void) {
  u8g2.setFont(u8g2_font_unifont_t_chinese1); //使用我們做好的字型
  u8g2.firstPage();
  do {
    u8g2.setCursor(0, 14);
    u8g2.print("傑森創工，歡迎你");
    u8g2.setCursor(0, 35);
    u8g2.print("ST7920 u8g2 SPI");   
    u8g2.setCursor(0, 60);
    u8g2.print("中文測試 15：20");
  } while ( u8g2.nextPage() );
  delay(1000);
}

真的是簡單又有彈性對吧！

st7290-spi