Marko Mäkelä’s old computers: Atari Video Computer System 2600

Presented in 1977, the Atari VCS 2600 was one of the first programmable video game systems. Its design is very simple, but it is extremely difficult to write programs for. The 2600 remained one of the most popular video game systems until the crash in 1984.

In these days, when games require way more storage and processing power than utility programs, it is educative to have a look at the technical details of the Atari Video Computer System 2600.

A 6502 variant running at about 1 MHz.
Video chip:
Stella, with registers mapped to $00$7F and $100$17F. Extremely rudimentary graphics, very few bytes of graphics memory. The main loop of each program must constantly write to Stella registers in order to display graphics and in order to control the start and stop of the vertical retrace phase.
Internal memory:
128 bytes of RAM on the 6532 RIOT (RAM, I/O and Timer) chip, which also contains the joystick interfaces and is responsible for producing sound effects.
External memory:
4 kilobytes of ROM on the cartridge; bank-switching is extremely difficult, since there is no read/write line on the cartridge port.

Here are some resources for the Atari 2600. I acquired my 2600 in November 1998, and I haven’t programmed anything for it yet.