Byte had a 2 article series in September and October 1985 of EGO, a 16 bit TTL cpu: https://www.americanradiohistory.com/Archive-Byte/80s/Byte-1985-09-10th-Ann… https://www.americanradiohistory.com/Archive-Byte/80s/Byte-1985-10.pdf Will "A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." --? Antoine de Saint-Exupery "The names of global variables should start with? ? // "? --?https://isocpp.org

<trim> Thank you. That is better reading than BYTE. 250 pages of full page ADS before you hit the text content. My only question is how much a Pound was in Canadian Dollars in 1976? Ben.

Ben said Well there's the EDUC-8, based on the PDP-8 instruction set and was published from 1974 to 1975 by Electronics Australia magazine, followed by a number of articles on building peripherals. https://en.wikipedia.org/wiki/EDUC-8 I have all the original magazine issues for it, but you can get them all in book form from Silicon Chip magazine these days https://www.siliconchip.com.au/Shop/3 Steve.

I built a dual-6809 in the late '70s - it was a brand-new, exciting part - and we used the E part for exactly that reason. The system used memory that had an access time that was better than the 4x clock, so that each processor could run at full speed. From: "cctalk" <cctalk at classiccmp.org> To: "Liam Proven" <lproven at gmail.com>, "cctalk" <cctalk at classiccmp.org> Sent: Tuesday, August 6, 2019 12:19:55 AM Subject: Re: MULTIPROCESSING FOR THE IMPOVERISHED Part 1: a 6809 Uniprocessor On Fri, Aug 2, 2019 at 11:15 AM Liam Proven via cctalk < cctalk at classiccmp.org> wrote: I disagree very much with the author's advice to use the MC6809 rather than the MC6809E. With the E version you have to supply a quadrature clock, but all that's required to generate that is a single-phase 4x clock (which you need with either the E or non-E part) and a single 74HCT74. If you feed your single-phase 4x clock into multiple 6809 (non-E) parts, their E clock phases won't match, but will be off by arbitrary multiples of 1/4 cycle, which makes the shared memory design unnecessarily difficult.

Ben wrote on Tue, 6 Aug 2019 13:47:59 -0600 I added a circuit to generate such a signal in my 1983 children's computer: http://www.smalltalk.org.br/fotos/pegasus1.jpg If I remember correctly, it only used half of a 74LS74. The notebook with the circuit is a bit hard for me to get to right now. It didn't work perfectly since it depended on there being a non memory cycle between fetching the instruction bytes and the data access. And that doesn't happen if you use the zero offset addressing mode. So I just wrote my assembler to never generate that. Instead it used a five bit offset with a value of zero. This wastes a byte and a clock cycle but I thought it was worth it. The extra signal was used to select between ROM and DRAM. This meant I couldn't fetch data from ROM nor execute code from DRAM but since the only program I was interested in was the Logo interpreter it seemed like a reasonable design. I did have a Logo compiler planned, which would not have worked with this. The 6809, and specially the 6809E were hardly cheap themselves. And their prices stayed stable while the 68000's dropped quite a lot. By late 1985 the difference was rather small. And the 6847/6883 chipset was expensive too, at around $40 for these two chips. I regretted using them as you can get a lot of TTLs for $40 and have far nicer video than they gave you, specially if you didn't care about the built in text modes. -- Jecel