----- Original Message ----- From: "Eric Smith via cctalk" <cctalk@classiccmp.org> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk@classiccmp.org> Sent: Wednesday, June 05, 2019 12:27 PM Subject: Re: Catatonic Rockwell AIM-65
> On Wed, Jun 5, 2019 at 1:15 AM Eric Smith <space...@gmail.com> wrote: > >> I might use those for something else, but I don't think those specific >> models aret useful for a base AIM-65. The 2332 ROMs in it (or 2532 EPROM >> are 24-pin devices, and the adapters you linked plug into 28-pin sockets. >> > > Mike pointed out to me in private email that I was mistaken. I read the > pages more carefully, and the first adapter he linked to is suitable for > 24-pin sockets. That looks pretty useful! -------------------- Odd; it was meant to go to the list as well but for some reason the return address only listed you. Actually, they both plug into 24-pin sockets; the difference between the two is that the 23xx adapter has some extra options, including accommodating positive-logic chip selects. At the risk of repeating what might have been obvious, the main reason I mentioned them in this AIM65 context is not only to trivially convert the 2532 pinout to a 27xx pinout; they do that, although using a 24-pin 2732 instead of a section of a larger 28-pin EPROM does require the Vcc jumper. As mentioned, the 2332 can also be directly replaced with a 2532 EPROM, and an MC68764/66 can replace the ubiquitous 24-pin 8KB 2364 type. But although they're useful in many systems including Commodore and even the IBM PC, they're particularly useful if you're actually using an AIM65: As mentioned, the AIM65's languages (except Pascal) are each in two 4KB ROMs, located in the same memory area and the same two sockets. This is convenient, especially considering the small base RAM, but it's a PITA if you want to switch, say, from BASIC to FORTH or even the 8K assembler, especially if the AIM is in an enclosure. These adapters let you select among languages with a switch instead of having to remove and replace the two ROM chips every time. BTW, the connections for the NOP generator are: Pins 29, 31 and 33 to pin 1 (GND) Pins 26, 27, 28, 30 and 32 to pin 8 (Vcc) https://easyeda.com/normal/6502_NOPpcb-ad5f77f0e6c0439f8e08cece619c407e Hope Rick has it working by now so he can play with it.
