Trouble with displaying images on a TFT LCD

[akelleher]

For an English project, I decided to use the 20x4 character LCD to display a word and its definition, and the 1.8" TFT LCD to display a picture related to the word.

Code: Select all

void setup(void) {
  tft.initR(INITR_GREENTAB); // initialize a ST7735R chip, green tab
  lcd.begin(20, 4);
  SD.begin(SD_CS);
tft.fillScreen(ST7735_BLACK);
lcd.setCursor(3,0);
lcd.print("English Project");
lcd.setCursor(3,2);
lcd.print("Alex Kelleher");
delay(3000);
lcd.clear();
}

void loop() {
drawGlee();
drawDelight();
drawCheerful();
drawGlad();
drawImpartial();
drawLament();
}

void drawGlee(){
  bmpDraw("glee.bmp",0,0);
  lcd.clear();
  lcd.setCursor(8,0);
  lcd.print("Glee");
  lcd.setCursor(2,2);
  lcd.print("Great delight or");
  lcd.setCursor(6,3);
  lcd.print("pleasure");
  delay(3000);
}

drawDelight(), drawCheerful(), etc. all follow the same format as drawGlee(); bmpDraw() is copied from the example in the ST7735 library.

This code works fine. It displays the initial nameplate with a black TFT, and then cycles through the six words with their corresponding images.

The problem comes when I add one more word. If I add

Code: Select all

void drawDejection(){
  bmpDraw("dejection.bmp",0,0);
  lcd.clear();
  lcd.setCursor(4,0);
  lcd.print("Dejection");
  lcd.setCursor(1,2);
  lcd.print("Lowness of spirits");
  delay(3000);
}

and call it from loop() right after the others, it breaks. All it does is show the nameplate with the black TFT, and then the character LCD clears, and then nothing else happens. But if I get rid of drawDejection(), it works fine again.

I'm really clueless about why this is happening. Thanks in advance.

[adafruit_support_bill]

The problem is likely related to your filename: "dejection.bmp".
The SD library only supports file names with up to 8 characters and a 3 character extension.

[akelleher]

Hmm, that explains a different problem I was having, but doesn't fix the main issue. Even with the file renamed to deject.bmp, the same thing happens. It seems that I can only have six at once- if I get rid of both the call and declaration for, as an example, drawImpartial(), then it works fine with drawDejection(). I have ten words total, and any six will work at once, but no more.

If I leave the function declarations for seven words in, but only call six, the program still breaks-- a function that's not called causes it to break. So I'm really confused.

[adafruit_support_bill]

If I leave the function declarations for seven words in, but only call six, the program still breaks-- a function that's not called causes it to break. So I'm really confused.

That sounds like a memory problem. There is not a lot of RAM in the Arduino, and when you run out, unpredictable things happen. Some helpful info here:http://itp.nyu.edu/~gpv206/2008/04/making_the_most_of_arduino_mem.html

[akelleher]

You're right, it turned out that I was running out of memory. Getting rid of extra string literals got me up to 9 out of 10 words (so close!), but no farther, so I ended up using PROGMEM from that link.

It also might be a good idea to mention that the SD library only supports 8 character filenames in the TFT LCD tutorial.

Thanks again.