I am starting out with the Master-System. I have been doing some analysis of the Tile, Tile-Map and Palette Data generated by the BMP conversion Tool bmp2tile as given on Maxim's SMS Tutorial.
I made some Example Tiles, one was an 8 Pixel Horizontal Line from the top of the First Tile, the Second was the same but on the next Line down and then I created an 8x8 Pixel Square all in a green Colour.
So the Pixel-Data as $00 $FF $00 $00 gives me a wholey filled Line of 8 Pixels. Format: B0:?, B1: 2 Nibbles for Pixel set, B2:?, B3:?. Does anyone know what the other 3 Bytes represent?
The colours. Each pixel can be one of sixteen colours, so the nibble tells it which colour to use. I probably can't explain it well right now, but I find it far easier to understand if it's written in binary. Here's your example in binary: (one byte per line)
00000000 11111111 00000000 00000000
What you do is read it top to bottom (each column is a pixel) - each vertical nibble gives the number of the colour to use in the palette. Here, they're all using the third colour. If you try adding different colours in to your test tiles (and pay attention to the ordering of the palette), it may help. Or perhaps writing the tile data as binary strings and editing them.