“This instructable will document and explain how to build a simple 8 bit basic computer system based upon an Arduino Mega and a simple cheap TFT display. I wanted to create an easy to build and cheap computer using only standard parts. What makes this 8 bit basic computer other than most of the currently available designs?
Lets take a look at the specifications:
- 8 bit ATmega processor at 16 Mhz;
- 8 K internal ram (4 K basic, 1 K heap, 3 K system);
- 4K + 32 K Eeprom storage (9 banks);
- SD card load and save of program and data;
- Efficient use of sram space because program code is tokenized;
- Extended basic language with graphics support;
- 27 real number variables (doubles) and math functions;
- 27 dynamic stings and string functions;
- 4 types of dynamic arrays (double,word,byte and bit);
- 320 x 240 pixel display with 512 colors;
- Fixed (8 x12) font giving 40 characters a line by 20 lines;
- USB (PS2) keyboard supported;
- 32 free programable I/O pins (back row of the Arduino Mega);
- 3D printable case, STL files can be downloaded.
This instructable will show you how I build it, because its all standard components, you could design your own version, make the case out of wood, leave the SD out witch will give you 512 bytes of extra sram, add other devices using SPI or I2C, the design is very universal to use and extend. I wrote the basic interpreter myself after a look at Tinybasic (and was very disappointed) and I wrote a complete redesign with my own ideas and optimizations in it. You can download the full code at my website, if you got any remarks, improvements of suggestions I would be glad to hear them and improve the code.”