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I had a Radio Shack Color Computer and Radio Shack actually sold a ROM cartridge (right alongside all the game cartridges) that was an editor/assembler. That's

I had a Radio Shack Color Computer and Radio Shack actually sold a ROM cartridge (right alongside all the game cartridges) that was an editor/assembler. That's how I got started in assembler. The manual that came with it covered using the assembler itself but only had a minimal overview of 6809 CPU assembly language. Pretty strange that you could pick up an assembly language IDE at your local Radio Shack store (with over 7000 locations, virtually every town in the U.S. had at least one Radio Shack). My teenaged self actually looked up Motorola in the phone book and called their offices asking for information on how to program their CPU. Some nice salesperson there took pity on me and sent me their 6809 reference manual along with a quick reference card for free. The manual was quite a sizable book that I wasn't fully ready to understand yet but that reference card was my constant companion. I still have it today. :-)

mjevans 1y ago
Those reference cards are very helpful. In college the embedded PC boards (generic) x86 and (I forget if it was a 68 or 65 series CPU) each included a CPU manual and quick assembly reference card. Seeing instructions grouped by how the decoder wanted them, it was much easier to see where a given entry would have 3 or 4 bits utilized to decode a sub function among a general class of instructions. Sadly I couldn't find a good link to a quick reference card, but there are some copies of the CPU manual on https://archive.org/search?query=6809 https://archive.org/search?query=6809 . A Wikipedia site is nowhere near as good as a properly typeset and slightly grouped to convey clarity card, but it's still useful https://github.com/Ta0uf19/Motorola-6809-Cheatsheet https://github.com/Ta0uf19/Motorola-6809-Cheatsheet
- mrandish 1y ago
  Here's a PDF that's identical to my Motorola 6809 Quick Reference Card: https://web.archive.org/web/20190714001537/http://chiclassiccomp.org/docs/content/computing/Motorola/A13262-16_MC6809MicroprocessorReferenceCard_0291.pdf https://web.archive.org/web/20190714001537/http://chiclassic...

mjevans 1y ago

Those reference cards are very helpful. In college the embedded PC boards (generic) x86 and (I forget if it was a 68 or 65 series CPU) each included a CPU manual and quick assembly reference card. Seeing instructions grouped by how the decoder wanted them, it was much easier to see where a given entry would have 3 or 4 bits utilized to decode a sub function among a general class of instructions. Sadly I couldn't find a good link to a quick reference card, but there are some copies of the CPU manual on https://archive.org/search?query=6809 https://archive.org/search?query=6809 . A Wikipedia site is nowhere near as good as a properly typeset and slightly grouped to convey clarity card, but it's still useful https://github.com/Ta0uf19/Motorola-6809-Cheatsheet https://github.com/Ta0uf19/Motorola-6809-Cheatsheet

mrandish 1y ago
Here's a PDF that's identical to my Motorola 6809 Quick Reference Card: https://web.archive.org/web/20190714001537/http://chiclassiccomp.org/docs/content/computing/Motorola/A13262-16_MC6809MicroprocessorReferenceCard_0291.pdf https://web.archive.org/web/20190714001537/http://chiclassic...