Hiletgoの2.8インチ TFT液晶で画像を表示してみた
こんにちは。
今回はSDカードに保存したBMP画像をArduinoNanoで読み込み、TFT液晶に表示させてみました。
Adafruit ILI9341のスケッチ例の"spitftbitmap"を自分が使いやすいように改造する形で行いました。
このTFT液晶モジュールはSDカードスロットが備わっているので、それを使用します。
配線は、
TFT_DC → 9
TFT_CS → 9
SD_CS → 4
TFT_MOSI → 11
TFT_MISO → 12
TFT_SCK → 13
SD_MOSI → 11
SD_MISO → 12
SD_SCK → 13
で接続しました。
ただし、このLCDは3.3V駆動なので、レベルコンバータを間に挟む必要があります。
- 出版社/メーカー: サンハヤト
- メディア: Tools & Hardware
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で、改変したソースコードがこちらです。
gochiusa.bmpをSDカードから読み込み、表示させるようになっています。
/*************************************************** This is our Bitmap drawing example for the Adafruit ILI9341 Breakout and Shield ----> http://www.adafruit.com/products/1651 Check out the links above for our tutorials and wiring diagrams These displays use SPI to communicate, 4 or 5 pins are required to interface (RST is optional) Adafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit! Written by Limor Fried/Ladyada for Adafruit Industries. MIT license, all text above must be included in any redistribution ****************************************************/ #include <Adafruit_GFX.h> // Core graphics library #include "Adafruit_ILI9341.h" // Hardware-specific library #include <SPI.h> #include <SD.h> // TFT display and SD card will share the hardware SPI interface. // Hardware SPI pins are specific to the Arduino board type and // cannot be remapped to alternate pins. For Arduino Uno, // Duemilanove, etc., pin 11 = MOSI, pin 12 = MISO, pin 13 = SCK. #define TFT_DC 9 #define TFT_CS 10 //TFT_RSTはつながなくてよいが、GNDに落としといたほうがいいかもしれない Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC); #define SD_CS 4 void setup(void) { Serial.begin(9600); tft.begin(); yield(); Serial.print("Initializing SD card..."); if (!SD.begin(SD_CS)) { Serial.println("failed!"); } Serial.println("OK!"); } //BMPファイルのファイル名は半角英数で8文字以下 void loop() { uint8_t r = 3; //回転角度 r=0~3 tft.setRotation(r); tft.fillScreen(ILI9341_BLUE); bmpDraw("gochiusa.bmp",0,0); //表示開始座標 /*for(uint8_t r=0; r<4; r++) { tft.setRotation(r); tft.fillScreen(ILI9341_BLUE); for(int8_t i=-2; i<1; i++) { bmpDraw("gochiusa.bmp", (tft.width() / 2) + (i * 120), (tft.height() / 2) + (i * 160)); } }*/ } // This function opens a Windows Bitmap (BMP) file and // displays it at the given coordinates. It's sped up // by reading many pixels worth of data at a time // (rather than pixel by pixel). Increasing the buffer // size takes more of the Arduino's precious RAM but // makes loading a little faster. 20 pixels seems a // good balance. #define BUFFPIXEL 20 void bmpDraw(char *filename, int16_t x, int16_t y) { File bmpFile; int bmpWidth, bmpHeight; // W+H in pixels uint8_t bmpDepth; // Bit depth (currently must be 24) uint32_t bmpImageoffset; // Start of image data in file uint32_t rowSize; // Not always = bmpWidth; may have padding uint8_t sdbuffer[3*BUFFPIXEL]; // pixel buffer (R+G+B per pixel) uint8_t buffidx = sizeof(sdbuffer); // Current position in sdbuffer boolean goodBmp = false; // Set to true on valid header parse boolean flip = true; // BMP is stored bottom-to-top int w, h, row, col, x2, y2, bx1, by1; uint8_t r, g, b; uint32_t pos = 0, startTime = millis(); if((x >= tft.width()) || (y >= tft.height())) return; Serial.println(); Serial.print(F("Loading image '")); Serial.print(filename); Serial.println('\''); // Open requested file on SD card if ((bmpFile = SD.open(filename)) == NULL) { Serial.print(F("File not found")); return; } // Parse BMP header if(read16(bmpFile) == 0x4D42) { // BMP signature Serial.print(F("File size: ")); Serial.println(read32(bmpFile)); (void)read32(bmpFile); // Read & ignore creator bytes bmpImageoffset = read32(bmpFile); // Start of image data Serial.print(F("Image Offset: ")); Serial.println(bmpImageoffset, DEC); // Read DIB header Serial.print(F("Header size: ")); Serial.println(read32(bmpFile)); bmpWidth = read32(bmpFile); bmpHeight = read32(bmpFile); if(read16(bmpFile) == 1) { // # planes -- must be '1' bmpDepth = read16(bmpFile); // bits per pixel Serial.print(F("Bit Depth: ")); Serial.println(bmpDepth); if((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressed goodBmp = true; // Supported BMP format -- proceed! Serial.print(F("Image size: ")); Serial.print(bmpWidth); Serial.print('x'); Serial.println(bmpHeight); // BMP rows are padded (if needed) to 4-byte boundary rowSize = (bmpWidth * 3 + 3) & ~3; // If bmpHeight is negative, image is in top-down order. // This is not canon but has been observed in the wild. if(bmpHeight < 0) { bmpHeight = -bmpHeight; flip = false; } // Crop area to be loaded x2 = x + bmpWidth - 1; // Lower-right corner y2 = y + bmpHeight - 1; if((x2 >= 0) && (y2 >= 0)) { // On screen? w = bmpWidth; // Width/height of section to load/display h = bmpHeight; bx1 = by1 = 0; // UL coordinate in BMP file if(x < 0) { // Clip left bx1 = -x; x = 0; w = x2 + 1; } if(y < 0) { // Clip top by1 = -y; y = 0; h = y2 + 1; } if(x2 >= tft.width()) w = tft.width() - x; // Clip right if(y2 >= tft.height()) h = tft.height() - y; // Clip bottom // Set TFT address window to clipped image bounds tft.startWrite(); // Requires start/end transaction now tft.setAddrWindow(x, y, w, h); for (row=0; row<h; row++) { // For each scanline... // Seek to start of scan line. It might seem labor- // intensive to be doing this on every line, but this // method covers a lot of gritty details like cropping // and scanline padding. Also, the seek only takes // place if the file position actually needs to change // (avoids a lot of cluster math in SD library). if(flip) // Bitmap is stored bottom-to-top order (normal BMP) pos = bmpImageoffset + (bmpHeight - 1 - (row + by1)) * rowSize; else // Bitmap is stored top-to-bottom pos = bmpImageoffset + (row + by1) * rowSize; pos += bx1 * 3; // Factor in starting column (bx1) if(bmpFile.position() != pos) { // Need seek? tft.endWrite(); // End TFT transaction bmpFile.seek(pos); buffidx = sizeof(sdbuffer); // Force buffer reload tft.startWrite(); // Start new TFT transaction } for (col=0; col<w; col++) { // For each pixel... // Time to read more pixel data? if (buffidx >= sizeof(sdbuffer)) { // Indeed tft.endWrite(); // End TFT transaction bmpFile.read(sdbuffer, sizeof(sdbuffer)); buffidx = 0; // Set index to beginning tft.startWrite(); // Start new TFT transaction } // Convert pixel from BMP to TFT format, push to display b = sdbuffer[buffidx++]; g = sdbuffer[buffidx++]; r = sdbuffer[buffidx++]; tft.writePixel(tft.color565(r,g,b)); } // end pixel } // end scanline tft.endWrite(); // End last TFT transaction } // end onscreen Serial.print(F("Loaded in ")); Serial.print(millis() - startTime); Serial.println(" ms"); } // end goodBmp } } bmpFile.close(); if(!goodBmp) Serial.println(F("BMP format not recognized.")); } // These read 16- and 32-bit types from the SD card file. // BMP data is stored little-endian, Arduino is little-endian too. // May need to reverse subscript order if porting elsewhere. uint16_t read16(File &f) { uint16_t result; ((uint8_t *)&result)[0] = f.read(); // LSB ((uint8_t *)&result)[1] = f.read(); // MSB return result; } uint32_t read32(File &f) { uint32_t result; ((uint8_t *)&result)[0] = f.read(); // LSB ((uint8_t *)&result)[1] = f.read(); ((uint8_t *)&result)[2] = f.read(); ((uint8_t *)&result)[3] = f.read(); // MSB return result; }
BMPファイルの作り方なんですが、MSペイントで画像を開き、320px × 240px に縮小し、24ビットマップで保存しました。
ただし、ファイル名は半角英数で8文字までみたいです。
実行すると...
表示されました!
ということで、BMP画像を表示することに成功しました。
拙い文章で申し訳ないです。
わからないことがあればお気軽にコメント欄までお寄せください。