From: Paul Pennington <paulpenn_at_knology.net>
> "Jay West" <jwest_at_classiccmp.org> said:
>
> > Well, actually, for the ET-3400 my interest isn't so much "collecting"
as
> it
> > is just plain technical interest. I would be happy with a replica of the
> > ETA-3400 to hook up to my ET3400. Is it a complex box to duplicate?
It's pretty much a 6820 PIA, two 2k ROMS (one for Tiny Basic, one for Fantom
II (terminal driven monitor,)) 2x to 8x 2114 RAMS, and a programmed 32x8
ttl ROM (74S188) to handle the address decoding for *all* those chips. The
rest of it is the 5,+12. -12 power supply and the glue between the PIA and
the RS232/TTY & cassette i/o.
There's also a modification back to the et-3400 needed changing the system
clock rate and a few line drivers.
The manauls have the rom code for the Fantom II monitor and even the 74188
but not the Heath/Pittman Tiny Basic.
> What do you want to do with it? I don't have one, but I understand an
> ETA-3400 adds a serial port, more memory, Tiny BASIC, and a cassette
> interface.
>
> The serial port is easily implemented with a 6850 and a one-chip
RS-232
> driver. Adding on more memory should also be one chip (64K x 8 static
RAM?)
> and maybe an EPROM to replace the 1K monitor ROM. Those are the only
things
> I am really interested in doing. Hopefully I can make it load and store
> programs down the serial port to a PC.
>
> As for the cassette port, not interested in going down that road
again!
I'll have to find that Kilobaud article where the dude wires up a floppy
interface to the et-3400...
> Has the manual for the ETA-3400 been scanned and put on a web site
> anywhere?
>
;)
- Mike: dogas_at_bellsouth.net
Received on Mon Mar 22 2004 - 18:55:17 GMT