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Hi John,
I saw your request for ADM 3A transformer, I think I have 3 of these terminals, I'm not sure if they are all working, but if I find that any of them are not, I might turn it into a parts donor. I need time to check them, and if they are all working, then I won't be so eager to condemn one. Separate I/O... at first I didn't fully understand this either, I got a little confused with some of the very early RAM chips that actually mapped an I/O port on the chip. But, after looking at one of the "Common I/O" data sheets, I understand it now as having either separate Data IN and Data OUT lines vs a common (bi-directional) Data bus. The 2101's use separate I/O, I know this from the COSMAC ELF. There is 1 pin that only serves as Data IN, and another pin that provides the Data OUT. Of course, on the ELF, these lines are simply tied together to provide a bidirectional access to the RAM's data. I think the photo discharge trick only works on Dynamic type RAM's... it doesn't make sense for a Static RAM to be affected by light, since it uses 6 transistors in a latch configuration. The Dynamic RAM uses only 1 transistor to gate it's capacitor to the sense amplifier, I believe the photo effect was that light affects the rate of this capacitors discharge. I've got a few other projects on the run at the moment, so I'll need some time to read the article before I can be of any further help. On the schematic, how many address lines and data lines are there??? Regards, Josh Date: Wed, 29 Apr 2015 15:03:10 -0700 From: jpars...@gmail.com To: n8vem...@googlegroups.com Subject: Re: [N8VEM-S100:6874] Altair Cyclops Info Wanted Josh,
An article somewhere told me the chip was an Intel 1001...but that is a 256 bit chip. My guess is that it is a static ram such as the 2102. Or do you think this was a dynamic chip? I found old Intel spec sheets here: http://www.intel-vintage.info/intelmemory.htm#710695270. I don't know what "with separate I/O" on the 2102 means, though. The 2102 pinout seems to match the Popular Electronics schematic. But I am not an EE, so I'm only guessing. Any thoughts on this? John -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to n8vem-s100+...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. |