4004 and IC history / was Re: Vintage computer photogallery

[Brent Hilpert]

dwight elvey wrote:
> 
> > From: hilpert at cs.ubc.ca
> >
> > dwight elvey wrote:
> >>
> >>> From: hilpert at cs.ubc.ca
> >>> ---snip--->
> >>> Regarding the 4040, I'm speculating as I've never dealt with one or come
> >>> across the pinout, but I suspect the 4040 essentially integrated the
> >>> 4004/4008/4009 into one larger package making it look more like a 'standard'
> >>> microproc in terms of signals/interface (somebody correct me if I'm wrong).
> >
> >> No, it was just a 4004 with, as I recall, two more instructions.
> >> It kept the 4004 multiplexed bus and connected to 4001's and 4002's,
> >> just like the 4004.
> >> As I recall, it had 4 times the address space with bank selects. I'd
> >> need to look at the specs again to be sure.
> >
> > Thanks for the correction, but why was it in such a larger package?
> > (4040 was a 28 or 40-pin package wasn't it?).
> 
> Hi
> 
>  It had more select lines for a larger address space. I think it added
> an Interupt and a single step as well. I believe that made up for the
> rest of the pins. It also had TTL compatible pins for many of the signal
> lines. I believe that required an extra power line as well. I recall that the
> reset line had inverted logic sense but that didn't effect the pin count.
>
>  It seems the 4040 was a 24 pin part.

Thanks, that matches up with the pinout Ben found. Along with some other contribs
it appears the 4040 was mostly software-arena improvements with relatively little
change to the hardware/interface environment.