Re: Identify this card?

[Eric Smith <eric-no-spam-for-me@brouhaha.com>]

"Peter de Vroomen" <peterv[at][spamblock]jaytown[dot]com> writes:
> Funny though, that they'd use 2114's together with a 6845. I believe DRAM's
> were cheaper than SRAM's then, as it is now. The 6845 handles the refresh of
> dynamic RAM's, so they could as well have used cheaper DRAM's. The only
> thing I can think of are that you'd need at least 8 DRAM's, and only 4
> 2114's.

You'd need 8 DRAMs, two multiplexers for the address, and a delay line
and some logic to generate the RAS and CAS strobes.

2114 chips were cheap during the early Apple II era.  Later the 6116
2K*8 SRAM was even more cost effective.

DRAMs did eventually appear in four-bit-wide configurations, but those
were not available when 80 column cards were being developed.

> Does anyone have schematics for an 80 column card for the Apple 2? I have
> lots of old Hercules compatible cards, I could make my own 80 column card

Videx provided excellent documentation on their Videoterm and Ultraterm
cards, including schematics and firmware source code.