This 6502 is as old as me and I test it

There is a lot of argument if the missing ROR instruction is a bug or not. Whatever it is, it was clearly intended to be there but was left out at the last minute, likely due to time constraints for the release for the CPU. Just a handful of months later an updated data sheet was released saying the instruction would be added into future versions of the chip. The ROM we wrote is able to identify (in a running system) if you have a CPU that has a non-functional ROR instruction. --- Info Possible TTL shift register TI 1A5008 --- Video Links ROM to test for the ROR bug on the Apple II: Pagetable ROR bug article: A viewer @DaftdogUK discovered what this is! See Page 102: MOS 6502 by Chuck Peddle: SWTPC 6800: Frank's Channel (IZ8DWF) Tech Time Traveller's Channel: The TV Typewriter (Shift register storage): Link to dumped 256 byte ROM Adrian's Digital Basement Merch store: Adrian's Digital Basement ][ (Second Channel) Support the channel on Patreon: -- Tools Deoxit D5: O-Ring Pick Set: (I use these to lift chips off boards) Elenco Electronics LP-560 Logic Probe: Hakko FR301 Desoldering Iron: Rigol DS1054Z Four Channel Oscilloscope: Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier: TL866II Plus Chip Tester and EPROM programmer: (The MiniPro) TS100 Soldering Iron: EEVBlog 121GW Multimeter: DSLogic Basic Logic Analyzer: Magnetic Screw Holder: Universal ZIP sockets: (clones, used on my ZIF-64 test machine) RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI) Plato (Clone) Side Cutters: (order five) Heat Sinks: Little squeezy bottles: (available elsewhere too) --- Links My GitHub repository: Commodore Computer Club / Vancouver, WA – Portland, OR – PDX Commodore Users Group --- Instructional videos My video on damage-free chip removal: --- Music Intro music and other tracks by: Nathan Divino @itsnathandivino