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The Motorola 6809 was (and still is) considered by many to be the most powerful and technically capable of the 8-bit CPUs. Its powerful PDP-inspired addressing

The Motorola 6809 was (and still is) considered by many to be the most powerful and technically capable of the 8-bit CPUs. Its powerful PDP-inspired addressing modes, flexible registers, deep instruction set, layered interrupts and multiple stack pointers fully supported writing position independent, re-entrant code. This enabled native multi-tasking, multi-user operating systems to be written such as the Unix-like OS/9. Unfortunately, Motorola misread the potential market size and wildly overpriced the CPU for the first few years of its life, which is why it wasn't selected for any of the lower cost, high-volume home computers of the era despite its clear advantages. Little known fact: Apple's initial Macintosh prototypes were based on the 6809 but the Mac was later upgraded to the the 6809's big brother the 68000 after Steve Jobs negotiated a very low price for the 68000. As a technical aside, the honor of best 8-bit CPU should correctly go to an even lesser-known 6809 variant, the second-source, Motorola-licensed Hitachi 6309. The 6309 was 6809 compatible and fabbed in CMOS allowing it to run almost twice the clock speed of the 6809, plus Hitachi added additional registers, instructions and optimizations even beyond the 6809.

_a_a_a_ 3y ago
"The added features of the 6809 were costly; the CPU had approximately 9,000 transistors compared to the 6800's 4,100 or the 6502's 3,500. While process improvements meant it could be fabricated cheaper than the original 6800, those same improvements were being applied to the other designs and so the relative cost remained the same. Such was the case in practice; in 1981 the 6809 sold in single-unit quantities for roughly six times the price of a 6502.[1] For those systems that needed some of its special features, like the hardware multiplier, the system could justify its price, but in most roles, it was overlooked." https://en.wikipedia.org/wiki/Motorola_6809 https://en.wikipedia.org/wiki/Motorola_6809
- jacquesm 3y ago
  Lucky for me Radio Shack inexplicably decided to use it in their Color Computer (I had a side job working in their stores so I had access to it) and when I started working full time for a bank a security guard there sold me his 'Dragon 32' micro which was a 1:1 clone of the CoCo. For the time this was a very interesting machine that used software where other computers used hardware, for instance, for audio in and out. The hardware was a bunch of resistors and a comparator (yay binary search) and replaced a whole bunch of costly ICs. I guess that's how they managed to keep the price of the machine down.

_a_a_a_ 3y ago

"The added features of the 6809 were costly; the CPU had approximately 9,000 transistors compared to the 6800's 4,100 or the 6502's 3,500. While process improvements meant it could be fabricated cheaper than the original 6800, those same improvements were being applied to the other designs and so the relative cost remained the same. Such was the case in practice; in 1981 the 6809 sold in single-unit quantities for roughly six times the price of a 6502.[1] For those systems that needed some of its special features, like the hardware multiplier, the system could justify its price, but in most roles, it was overlooked." https://en.wikipedia.org/wiki/Motorola_6809 https://en.wikipedia.org/wiki/Motorola_6809

jacquesm 3y ago
Lucky for me Radio Shack inexplicably decided to use it in their Color Computer (I had a side job working in their stores so I had access to it) and when I started working full time for a bank a security guard there sold me his 'Dragon 32' micro which was a 1:1 clone of the CoCo. For the time this was a very interesting machine that used software where other computers used hardware, for instance, for audio in and out. The hardware was a bunch of resistors and a comparator (yay binary search) and replaced a whole bunch of costly ICs. I guess that's how they managed to keep the price of the machine down.