The 8212 is a weird kind of chip because it's a multi-function chip designed to eliminate 2-3-4 different chips in an 8008/8080/8085 system. It includes an 8-bit D-type latch, address selection logic and an interrupt generator. The data book I have shows it as being used as a status latch for the 8080, a standard gated buffer, a bi-directional buss driver (with two chips), an interrupting input port, a port to jam a RST instruction into the data buss during an interrupt acknowledge cycle, an output port, and an address buss latch. So, I guess it depends on the circuit whether you can replace it with another chip or not. There was also an 8228 system controller chip which performed a similar buss status latch using WR, DBIN and HLDA plus the data buss to provide a bi-directional data buss driver and control signals (INTA, MEMR/W, IOR/W). There is a 6-part article on my Web site from Popular Electronics (9/81) that shows this setup. Rich -- Rich Cini Collector of Classic Computers Build Master and lead engineer, Altair32 Emulator From: Don Caprio <cap...@uxpro.com> Reply-To: <n8vem...@googlegroups.com> Date: Monday, August 20, 2012 8:12 PM To: <n8vem...@googlegroups.com> Subject: Re: [N8VEM-S100:1064] 8T97 Substitutions On Mon, Aug 20, 2012 at 4:59 PM, Richard Cini <rich...@verizon.net> wrote: Don -- -- ------------------------------- Don Caprio cap...@uxpro.com http://www.uxpro.com (925) 240-UNIX |