Neil Andretti

@masterhit.bsky.social

aka webdoktor / masterhit / Nils Andreas KIM-1 & 6502 enthusiast, gardening professional, dog and cat lover, Blog: netzherpes.de

The 6502's JSR pushed the return address minus one onto the stack. RTS pulled it and added one before jumping. Why minus one? Because the 6502 incremented the program counter before fetching the next byte anyway. It saved a cycle at the cost of confusing every programmer who looked at the stack.

The RAMpager is a MTU banked RAM expansion for the KIM-1: the board supports up to 1MB (that's three orders of magnitude above more than the original 1152 bytes!) of memory and maps it to a 4KB window placed between 2000h and FFFFh. www.pcbway.com/project/shar...

RAMpager (KIM-1) - Share Project - PCBWay

The RAMpager is a MTU banked RAM expansion for the KIM-1: the board supports up to 1MB (that's three orders of magnitude above more than the original 1152 bytes!) of memory and maps it to a 4KB window...

pcbway.com

In Frankfurt, Germany there will be an Iron Man this sunday. At the peak of the heatwave. Let‘s go and let Darwin decide! I love cycling and running and swimming, but please let them pay for their medical bills themself when they collaps.

SYM-1 by Synertek was another KIM-1 competitor. Compatible enough to run KIM software, different enough to justify its own manual. The 6502 trainer market of the late '70s was surprisingly crowded.

Chuck Peddle sold the 6502 for $25 when competing chips cost $150+. He didn't just design a processor - he made microcomputing affordable. The Apple II, Commodore 64, NES, and Atari 2600 all exist because of that price.