I have an Adafruit Feather RP2040 Adalogger with bmp files on the feather’s SD card that I want to display on an ST7796S TFT SPI screen. The closest I have gotten is with this code:
/***************************************************
This is our Bitmap drawing example for the Adafruit HX8357 Breakout
----> http://www.adafruit.com/products/2050
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_ST7796S_kbv.h"
#include <SPI.h>
#include "SdFat.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_RST 8
#define TFT_DC 9
#define TFT_CS 10
// Use hardware SPI (on Uno, #13, #12, #11) and the above for CS/DC
Adafruit_ST7796S_kbv tft = Adafruit_ST7796S_kbv(TFT_CS, TFT_DC, TFT_RST);
#define SD_CS_PIN 23
SdFat SD;
//FsFile myFile;
SdSpiConfig config(SD_CS_PIN, DEDICATED_SPI, SD_SCK_MHZ(16), &SPI1);
void setup(void) {
Serial.begin(9600);
tft.begin();
tft.fillScreen(ST7796S_BLUE);
Serial.print("Initializing SD card...");
if (!SD.begin(config)) {
Serial.println("failed!");
}
Serial.println("OK!");
bmpDraw("AP1.bmp", 0, 0);
}
void loop() {
}
// 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) {
FsFile 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(); // Start TFT transaction
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(); // 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.pushColor(tft.color565(r,g,b));
} // end pixel
} // end scanline
tft.endWrite(); // End last TFT transaction
Serial.print(F("Loaded in "));
Serial.print(millis() - startTime);
Serial.println(" ms");
delay(1000);
} // 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(FsFile &f) {
uint16_t result;
((uint8_t *)&result)[0] = f.read(); // LSB
((uint8_t *)&result)[1] = f.read(); // MSB
return result;
}
uint32_t read32(FsFile &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;
}
It gives a Serial output of:
Initializing SD card...OK!
Loading image 'AP1.bmp'
File size: 1027962
Image Offset: 138
Header size: 124
Bit Depth: 24
Image size: 582x588
Loaded in 1372 ms
However it does not display anything other than static on the screen. The information about the file on the SD card is accurate, and it’s consistently accurate when I choose a different file. The file just doesn’t show up on the screen. I will eventually want to display the images in rapid succession to play a video but I am working on 1 frame atm.
It seems like it is able to find, open and read the file, but not able to push it to the display.
Any ideas on where I am going wrong?
