E&L Instruments Fox 1 Z80 Trainer chip questions

[Glen Slick]

On 10/10/05, ROBO5.8 <robo58 at optonline.net> wrote:
> Hi Folks,
>
> I recently obtained a used E&L Instruments MT-80Z microprocessor trainer.
> My goal is to teach my kids a little about microprocessors.
>
> The trainer has 3 empty IC sockets U1-40 pin, U10-40 pin and U-11-28 pin.
> The parts are missing on the board that contains the keyboard and 7 segment
> displays.  Neither of which work, so I suspect those empty sockets require a
> chip or two for operations.
>
> The parts are probably Zilog or Intel PIO's and a CTC (Counter Clock Timer).

Good guess.  U10 is an optional PIO. U11 is an optional CTC. U1 is
where the Z80 goes in the MPF-1.  On the MT-80Z the Z80 is moved to
the second PCB and U1 is empty on the original PCB.

Schematics for the original MPF-1 board can be found here:
http://themotionstore.com/leeedavison/z80/mpf1/index.html

I have never found an online schematic or manual for the MT-80Z.  The
monitor EPROM in the MT-80Z I have is slightly different than the
monitor EPROM in the MPF-1, but I think the changes are very minor.