Atari 65XE

Here is my first computer… In fact it is not the same computer I had, as I sold mine for big money and bought cool computer Amiga 500. But this blog post is not about Amiga, but about my old Atari.

Atari 65XE is younger version of Atari 800. It was second attempt of Atari and Warner Bros. to make money from old 8 bit technology. The computer was popular and was sold in eastern Europe (soviet block) countries. The technology is newer than in old 800 and 65XE was easily converted to 128kb version Atari 130XE. Especially last versions with 4 DRAM chips.

Atari 65XE is based on 6502 CPU running ant 1.8MHz. Computer has 24kb or ROM with OS and BASIC and 64kb of RAM. All RAM, ROM, custom graphics, peripheral and other chips were located in same address space. It is possible to switch off the ROM, so RAM available for user can be increased.

The computer has more custom chips than ZX Spectrum. These customs chips made this computer impossible to clone using simple TTL logic. Some chips were debugged- FREDDY (MMU) chip was cloned and updated to handle even more RAM.

Main advantage against ZX Spectrum is, that computer has GPU (graphics processor) and hardware sprites. Also, it has more advanced audio hardware than original speccy. The audio is 4 independent audio synthesizers. GPU has only 2 commands, but it makes some interesting video effects. Like changing the screen resolution on same scree and also it allows to change color palette on every scanline. This introduced HAM (hold and modify) mode, more expanded in Amiga computer.

Such GPU reduce CPU load and RAM needed to game. The original 2600 game system used similar hardware and it was running game without RAM! (There is only ten or twenty bytes of RAM- bytes, not kilobytes.)

I was using this computer about 20 years ago and I forgot all the tricks. So the testing software for my friend Znaika is only in text mode. It is running in GRAPHICS 0 mode. It is hardware only, text mode and the text is changing very fast.

Also, I build AIO2PC (SIO2PC) interface for this computer and mine P4 with all it’s 3GHz is working as slave for atari and emulating floppy drive. I downloaded ALL games available for this computer and put in one folder. (Warez!)