A really Great Article on the Motorola 6800 Family.. Myself, as a Tandy Color Computer user since 2012 and a Tano Dragon Users since 2016, adding the Hitachi CMOS HD6309 is going another level in the MC6809 Family. Many people replace the MC6809 with the HD6309 because of the tremendous advancements available.. Advancements that Hitachi didn't tell Motorola about.. If you can, please add a Fourth Part to your series... https://en.wikipedia.org/wiki/Hitachi_6309
Turbo9 is a really interesting project from the University of Florida with a Verilog implementation of an updated, pipelined 6809 instruction set. They've used it for SOC devices that don't need more than a 16-bit path but benefit from less area and power than 32/64-bit instruction sets.
Intel won not because the 8080 was technically better but because a whole family of 8080 chips were developed including the 8085 and the z80 compatible chip. The final nail on the coffin was the 8088 which was a 16-bit chip but allowed cheaper 8-bit memory to be used because you need one ram chip for each bit plane of the memory so ram cards could be built with only eight chips!
It was a mistake not to have 2 index registers, or even 3. The stack and data pointer are a part of almost all algorithmic languages (algol, pascal, C at the time) and so it would be clumsy to have to always be loading and storing the stack register to get variables off the stack! And a third register could point to the heap! I have a Hayes Microprocessor Guide ($30 in ~1977) that overviews 6800, 8080, 6502, 1802, and other microprocessors - all in 1 volume!
If any DEC mini had influence on the MC6800 architecture, it was the PDP-11, not so much the PDP-8. The ONLY similarity to the PDP-8 is that both are accumulator-based architectures, while the PDP-11 has 8 general-purpose reisters. (Well, really 7, but who's counting.) Even there, the MC6800 is a bit closer to the PDP-11 by virtue of having TWO accumulators.
But the big similarity with the PDP-11 is the instruction set. The PDP-8 has only 8 instructions, none of which are very similar to the MC6800. The PDP-11 has a lot of instructions, and almost all of them have equivalents in the MC6800, even with related mnemonics.
A really Great Article on the Motorola 6800 Family.. Myself, as a Tandy Color Computer user since 2012 and a Tano Dragon Users since 2016, adding the Hitachi CMOS HD6309 is going another level in the MC6809 Family. Many people replace the MC6809 with the HD6309 because of the tremendous advancements available.. Advancements that Hitachi didn't tell Motorola about.. If you can, please add a Fourth Part to your series... https://en.wikipedia.org/wiki/Hitachi_6309
Turbo9 is a really interesting project from the University of Florida with a Verilog implementation of an updated, pipelined 6809 instruction set. They've used it for SOC devices that don't need more than a 16-bit path but benefit from less area and power than 32/64-bit instruction sets.
https://github.com/turbo9team/turbo9
Intel won not because the 8080 was technically better but because a whole family of 8080 chips were developed including the 8085 and the z80 compatible chip. The final nail on the coffin was the 8088 which was a 16-bit chip but allowed cheaper 8-bit memory to be used because you need one ram chip for each bit plane of the memory so ram cards could be built with only eight chips!
It was a mistake not to have 2 index registers, or even 3. The stack and data pointer are a part of almost all algorithmic languages (algol, pascal, C at the time) and so it would be clumsy to have to always be loading and storing the stack register to get variables off the stack! And a third register could point to the heap! I have a Hayes Microprocessor Guide ($30 in ~1977) that overviews 6800, 8080, 6502, 1802, and other microprocessors - all in 1 volume!
If any DEC mini had influence on the MC6800 architecture, it was the PDP-11, not so much the PDP-8. The ONLY similarity to the PDP-8 is that both are accumulator-based architectures, while the PDP-11 has 8 general-purpose reisters. (Well, really 7, but who's counting.) Even there, the MC6800 is a bit closer to the PDP-11 by virtue of having TWO accumulators.
But the big similarity with the PDP-11 is the instruction set. The PDP-8 has only 8 instructions, none of which are very similar to the MC6800. The PDP-11 has a lot of instructions, and almost all of them have equivalents in the MC6800, even with related mnemonics.