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Eight More '8-Bit Era' Microprocessors
11–20 of 37 posts
Re: Eight More '8-Bit Era' Microprocessors
#12The Signetics 2650 found its way into a bunch of arcade games by lieu of British company Century Electronics. I have a conversion kit of theirs installed into a Donkey Kong Jr. board, which outright replaces DK Jr.'s Z80 with a daughterboard containing the CPU. Always wondered why they chose that in particular, it's not a very common chip, and just using the Z80 that was there and replacing the ROMs was the more comm…
Zaccaria pinballs I think used it pretty heavily as well. Again, no clear explanation there either.
Re: Eight More '8-Bit Era' Microprocessors
#13Earlier quoted context omitted.
Way less than a million! I believe usually in the order of thousands.
Indeed. The 6502 had 3510 enhancement transistors and 1018 depletion transistors for a total of 4528...
With the layout fitting entirely on a large sheet of paper: https://archive.archaeology.org/1107/features/mos_technology...
Re: Eight More '8-Bit Era' Microprocessors
#14Re: Eight More '8-Bit Era' Microprocessors
#15The Signetics 2650 found its way into a bunch of arcade games by lieu of British company Century Electronics. I have a conversion kit of theirs installed into a Donkey Kong Jr. board, which outright replaces DK Jr.'s Z80 with a daughterboard containing the CPU. Always wondered why they chose that in particular, it's not a very common chip, and just using the Z80 that was there and replacing the ROMs was the more comm…
The 2650 was one of the first microprocessors on the market you could buy, it was shockingly simple to design, and had some dedicated I/O lines. Look up the reference schematic and compare to what a 6502 or Z80 needs. It was used in a lot of early embedded systems. It makes sense in that light
Re: Eight More '8-Bit Era' Microprocessors
#16Earlier quoted context omitted.
Way less than a million! I believe usually in the order of thousands.
The Motorola 68000, a great CPU with 32-bit operands, was initially implemented with 68,000 transistors. The model number was decided long before the transistor-level design was finalized.
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Re: Eight More '8-Bit Era' Microprocessors
#17Slightly orthogonal, but I'm curious how much effort is going into capturing historic hardware in accurate FPGA representation?
There'll come a day when the final physical 6502, 80486 (etc etc) powers off for the final time, and it seems like these technologies would be worth preserving. (I'm sure this is much easier said than done, not trying to minimise the effort involved.)
Is there a project that does something like this?
Re: Eight More '8-Bit Era' Microprocessors
#18Slightly orthogonal, but I'm curious how much effort is going into capturing historic hardware in accurate FPGA representation? There'll come a day when the final physical 6502, 80486 (etc etc) powers off for the final time, and it seems like these technologies would be worth preserving. (I'm sure this is much easier said than done, not trying to minimise the effort involved.) Is there a project that does something l…
Quite a few. There's a great project to do cycle accurate emulation of the 8086, too, which is more my area of interest than 6502.
Note that 6502s are still being produced, albeit in a modern CMOS version.
Re: Eight More '8-Bit Era' Microprocessors
#19Earlier quoted context omitted.
Way less than a million! I believe usually in the order of thousands.
The Motorola 68000, a great CPU with 32-bit operands, was initially implemented with 68,000 transistors. The model number was decided long before the transistor-level design was finalized.
I think there were actually 68000 transistor positions. In the ROMs and PLAs not every potential transistor is populated but the missing ones were counted as well. But the number of actual transistors is only slightly smaller so it doesn't really matter.
Re: Eight More '8-Bit Era' Microprocessors
#20Slightly orthogonal, but I'm curious how much effort is going into capturing historic hardware in accurate FPGA representation? There'll come a day when the final physical 6502, 80486 (etc etc) powers off for the final time, and it seems like these technologies would be worth preserving. (I'm sure this is much easier said than done, not trying to minimise the effort involved.) Is there a project that does something l…
Quite a few. There's a great project to do cycle accurate emulation of the 8086, too, which is more my area of interest than 6502. Note that 6502s are still being produced, albeit in a modern CMOS version.
Most fun I ever had with a 6502 was when I realized that, at 1 MHz, I could do 250,000 average instructions per second. So I divided my monitor up into 20 boxes to have 12500 (fairly complex!) instructions per per second for each box. I used them to separately animate the contents of each box differently.
Just calculating or shuffling data around was invisible. With that visualization I first realized how much stuff could be done with a 1MHz CPU.