RAMCAL again

[jsg at donet.com]

   In message <199906092156.RAA23087 at jsgpc.mrcday.com>, you write:
 
| what if....
| 
| How about a small Dallas battery backed-up RAM (16k) piggy back on the
| EPROM. Put the RAM in the table space (0x8000-0xafff) and leave the
| EPROM in 0xb0000-0xffff (program text). One wire mode to bring r/!w
| from the cpu.  The aldl would already have the commands to write to
| the RAM.  load the RAM with the table values on the bench, and then
| modify on the fly later.
| 
| This might work on 165's and 730's.... very cheap... comments?
| 
| john gwynne

ok... I'm thinking off the top of my head again, sorry... let's just
get a DS1230Y/AB 256K NV SRAM and plug it in (re-wire pins 1 and 27;
jumping r/!w to the cpu). Other than a separate board to do the first
program down load from a pc, the hardware is done. We could then
modify anything on the fly through the aldl (aldl's that were bi-dir
8192 and supported a write function, of course... I'm thinking late
model 165's and 730's as the target).

john gwynne