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How to read bytes from a SD card?
I have the following piece of code which opens a Bitmap from the SD card and outputs the width to the serial monitor.
How is a BMP image stored on a SD card?
The common BMP format is to store the image in raster fashion from the bottom upwards but the graphics and plot windowing expects an image to be drawn top down.
How to draw image from SD card on Arduino?
The main changes to the ILI9341 library are to enhance speed and to add the pushColors () function, one to handle integer arrays (for BMP drawing) and one for byte arrays (raw images). In the zip file you will find a folder containing images, put these on a FAT formatted SD card for the Arduino to read (not in a directory!).
Is there an Arduino display with a bitmap?
These displays are available at low cost on eBay. The library and function should work OK with other displays that use that driver chip. By using an optimized version of the Adafruit_GFX library and an efficient function a raw 320×240 full colour bitmap can be plotted to the screen in 660ms, not bad for a humble UNO.
Is it possible to read a file byte by byte?
You do not test for fopen failure, causing undefined behavior if the file does not exist or cannot be open. You are not reading the file byte by byte, instead you are reading blocks of 4900 bytes and just print one byte of each block.
How many characters per byte in% X?
The conversion format %x outputs 1 or 2 characters per byte depending on the byte value. This is a problem is the file contents are 0x00, 0x01, 0x10 and 0x11, which respectively produce 0, 1, 10 and 11, hence the apparent misaligned input.
Is the source file a collection of 0 and 1 bytes?
Given the hex-decimal view of your input file, and the expectation that the output is all 0 and 1, it is unlikely that the source file is a collection of bytes consisting of 0 and 1. Instead, it likely contains bytes from 0 to 256, and each byte is a collection of 0 and 1 bits. Print it as follows: