Help with SD card BMP reader (model train simulator)

S

SteveCS

Well-known member
Hi all

I have a 1.8" ST7735 TFT screen, all working fine.

I would like to load BMP images onto it, but the only example I could find is the following one:

https://simple-circuit.com/draw-bmp-images-arduino-sd-card-st7735/

My code has the correct pins for a 4.1 declared, below is the original code from the online example (which compiles the same errors). The Screen works fine, this is some kind of Arduino to Teensy issue - I think

Code: 
/*
 * Draw Bitmap images on ST7735 TFT display using Arduino.
 * The Arduino loads BMP format images from SD card and display
 *   them on the ST7735 TFT.
 * Reference: Adafruit spitftbitmap.ino example.
 * This is a free software with NO WARRANTY.
 * https://simple-circuit.com/
 */
 
#include <Adafruit_GFX.h>    // include Adafruit graphics library
#include <Adafruit_ST7735.h> // include Adafruit ST7735 display library
#include <SPI.h>             // include Arduino SPI library
#include <SD.h>              // include Arduino SD library
 
// define ST7735 TFT display connections
#define TFT_RST  5   // reset line (optional, pass -1 if not used)
#define TFT_CS   6   // chip select line
#define TFT_DC   7   // data/command line
 
#define button   2  // button pin
 
// initialize Adafruit ST7735 TFT library
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);
 
void setup(void) {
  Serial.begin(9600);
 
  pinMode(TFT_CS, OUTPUT);
  digitalWrite(TFT_CS, HIGH);
  pinMode(button, INPUT_PULLUP);
 
  // initialize ST7735S TFT display
  tft.initR(INITR_BLACKTAB);
 
  tft.fillScreen(ST77XX_BLUE);
 
  Serial.print("Initializing SD card...");
  if (!SD.begin()) {
    Serial.println("failed!");
    while(1);  // stay here
  }
  Serial.println("OK!");
 
  File root = SD.open("/");  // open SD card main root
  printDirectory(root, 0);   // print all files names and sizes
  root.close();              // close the opened root
 
}
 
void loop() {
  File root = SD.open("/");  // open SD card main root
 
  while (true) {
    File entry =  root.openNextFile();  // open file
 
    if (! entry) {
      // no more files
      root.close();
      return;
    }
 
    uint8_t nameSize = String(entry.name()).length();  // get file name size
    String str1 = String(entry.name()).substring( nameSize - 4 );  // save the last 4 characters (file extension)
 
    if ( str1.equalsIgnoreCase(".bmp") )  // if the file has '.bmp' extension
      bmpDraw(entry.name(), 0, 0);        // draw it
 
    entry.close();  // close the file
 
    delay(500);
    while( digitalRead(button) ) ;  // wait for button press
  }
}
 
// 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, uint8_t x, uint16_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;
  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
        w = bmpWidth;
        h = bmpHeight;
        if((x+w-1) >= tft.width())  w = tft.width()  - x;
        if((y+h-1) >= tft.height()) h = tft.height() - y;
 
        // Set TFT address window to clipped image bounds
        tft.startWrite();
        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) * rowSize;
          else     // Bitmap is stored top-to-bottom
            pos = bmpImageoffset + row * rowSize;
          if(bmpFile.position() != pos) { // Need seek?
            tft.endWrite();
            bmpFile.seek(pos);
            buffidx = sizeof(sdbuffer); // Force buffer reload
          }
 
          for (col=0; col<w; col++) { // For each pixel...
            // Time to read more pixel data?
            if (buffidx >= sizeof(sdbuffer)) { // Indeed
              bmpFile.read(sdbuffer, sizeof(sdbuffer));
              buffidx = 0; // Set index to beginning
              tft.startWrite();
            }
 
            // Convert pixel from BMP to TFT format, push to display
            b = sdbuffer[buffidx++];
            g = sdbuffer[buffidx++];
            r = sdbuffer[buffidx++];
            tft.pushColor(tft.color565(r,g,b));
          } // end pixel
        } // end scanline
        tft.endWrite();
        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;
}
 
 
void printDirectory(File dir, int numTabs) {
  while (true) {
 
    File entry =  dir.openNextFile();
    if (! entry) {
      // no more files
      break;
    }
    for (uint8_t i = 0; i < numTabs; i++) {
      Serial.print('\t');
    }
    Serial.print(entry.name());
    if (entry.isDirectory()) {
      Serial.println("/");
      printDirectory(entry, numTabs + 1);
    } else {
      // files have sizes, directories do not
      Serial.print("\t\t");
      Serial.println(entry.size(), DEC);
    }
    entry.close();
  }
}
 
// end of code.

Using a Teensy 4.1 and I get all the following errors which I don't really understand:

C:\Users\steve\Documents\Steve - Arduino coding\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino: In function 'void bmpDraw(char*, uint8_t, uint16_t)':
C:\Users\steve.croot\Documents\Steve - Arduino coding\Train scenario\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino:249:12: error: 'tft' was not declared in this scope
if((x >= tft.width()) || (y >= tft.height())) return;
^
C:\Users\steve\Documents\Steve - Arduino coding\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino:257:40: warning: converting to non-pointer type 'int' from NULL [-Wconversion-null]
if ((bmpFile = SD.open(filename)) == NULL) {
^
C:\Users\steve\Documents\Steve - Arduino coding\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino:296:23: error: 'tft' was not declared in this scope
if((x+w-1) >= tft.width()) w = tft.width() - x;
^
C:\Users\steve\Documents\Steve - Arduino coding\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino:297:23: error: 'tft' was not declared in this scope
if((y+h-1) >= tft.height()) h = tft.height() - y;
^
C:\Users\steve\Documents\Steve - Arduino coding\Trainline_SFX_v5_-_New_screen\Trainline_SFX_v5_-_New_screen.ino:300:9: error: 'tft' was not declared in this scope
tft.startWrite();
^


What do I need to add/change?
Thank you
 
I will take a quick look, however you might look at our library for ST7735/89, which is installed with Teensyduino (ST7735_t3)

We have an example with it: spitftbmp which will display a bitmap on the display.
Have not tried it in a while, but.
 
Warning your source code posted or the unline code does not match what you compiled.

As there are only 245 lines in it. And the first line with error is line 249.

The code you posted builds fine on my machine using Arduino IDE 2.0.1 (actually I did with nightly build, but)
It did show some compiler warnings that I would probably fix if it were mine.

Like change: void bmpDraw(const char *filename, uint8_t x, uint16_t y) {

(added const)

Changed:
Code: 
  // Open requested file on SD card
  if ((bmpFile = SD.open(filename)) == NULL) {
to
Code: 
  // Open requested file on SD card
  bmpFile = SD.open(filename);
  if (!bmpFile) {
 
OK. The errors are still the same, just different line numbers.

The errors now are just the 'tft' not declared ones
 
Sorry not sure how to help here as it builds fine on my machine with the sources in your post.


Maybe post what you are actually building.
Code: 
// initialize Adafruit ST7735 TFT library
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);
Where tft is defined as line 23.

You might try doing a format operation (ctrl+t on my windows machine) and see if
something obvious like functions not starting back in column 1 shows up. which can happen if comments or brackets get out of allignment
 
OK thanks Kurt.

Your ST7735_t3 example for opening a BMP loads fine, it just cannot find the BMP file for some reason. It's the correct dimension (160x128), so I will have to address that later.
I will have a play
 
If you have not already done so you should change the
#define SD_CS 4 // CS for SD card, can use any pin

to instead use BUILTIN_SDCARD

(Assuming you are using the SD on the T4.1).

You can also remove the line: pinMode(SD_CS, INPUT_PULLUP); // keep SD CS high when not using SD card
 
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