The really interesting thing (to me anyway) is just how it works. The cells are 3T1C (3 transistor, 1 capacitor).
There’s a good diagram here: https://electronics.stackexchange.com/questions/477173/the-detailed-working-steps-of-the-dram-3t1c-cell I assumed that the photons were just allowing charge to escape across the capacitor. Terry corrected me. The transistor labeled “T2” in the above diagram is what is light sensitive. When struck by photons, T2 allows charge to leak to ground, discharging the cap and “flipping” the bit to zero. Bill From: Eric Smith [mailto:space...@gmail.com] Sent: Wednesday, June 10, 2020 12:38 PM To: William Sudbrink; General Discussion: On-Topic and Off-Topic Posts Subject: Re: Ever seen a Cromemco Cyclops in the wild? On Tue, Jun 9, 2020 at 6:14 PM William Sudbrink <wh.sudbr...@verizon.net> wrote: No, I'm afraid not. I can tell you from both personal experience and from the designer (Terry Walker) that the chip is either a Mostek MK4008P-9 or an AMI S4008-9. I have used both chips. See my web page: http://wsudbrink.dyndns.org:8080/cyclops/index.html You obviously must be correct, and use of a DRAM makes much more sense than an SRAM. It's possible that an SRAM could be made to work as an image sensor, but it would not be anywhere near as sensitive as a DRAM. When, back in 1975, I compared the pinout to the data books I had on hand, and observed that it exactly matched the 2102, and didn't search any further. I had no idea that the MK4006 and MK4008 dynamic RAMs happen to have the same pinout as the 2102 static RAM. Intel's own 1K DRAMs (1103 PMOS, 2105 NMOS) do not share that pinout. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
