Running a Z8-02 MPD on a breadboard

[Eric Smith]

Some time back I acquired a Zilog Z8-02 MPD. This is the bond-out
version of the Z8 microcontroller. The normal Z8 contained 2K of
internal masked ROM and was packaged in a 40-pin DIP. The Z8-02 had no
masked ROM (or possibly the masked ROM was disabled), and the address
and data buses for the internal ROM, along with a few clock and
control signals, were brought out to the extra 24 pins of a 64-contact
ceramic leadless quad-in-line package (QUIP). Typically for emulation
it would be used with a 2716 EPROM, or 2KB of RAM with address and
data multiplexers for a fancy emulator.

The ceramic leadless QUIP package was used for bondouts from Intel and
Zilog, and later, for the Intel iAPX 432 components. Later it was
replaced with the square JEDEC ceramic leadless package. Note that the
ceramic leadless QUIP is unrelated to the more common leaded QUIP
packages used by NEC, Rockwell, and Motorola.

Unlike many modern leadless packages (DFN, QFN, BGA), the ceramic
leadless QUIP is intended for use only in a socket, which was made by
3M. Today the sockets are even harder to find than the chips that
require them.

I designed a simple QUIP adapter for use with solderless breadboards,
and wired up a Z8-02 MPD along with a 28C16 EEPROM for the program
memory, a 62256 static RAM, address latch, and decoder. I programmed a
copy of the Z8671 Basic/Debug interpreter into the EEPROM. To my
amazement, it worked the first time.

Photos:
    https://www.flickr.com/photos/22368471@N04/sets/72157652653732622

The last "photo" is a screen shot of Kermit talking to it. I've
entered an inefficient program to search for primes, and the screen
shot shows it being LISTed, RUN, and then stopped after a few primes
have been found.

Not shown, I printed the value of some of the interpreter's globals,
to verify that the static RAM was recognized properly. (The
interpreter can actually provide minimal functionality with no
external memory!)

While Zilog only claimed it to be a subset of Dartmouth BASIC, the
interpreter does not include the FOR statement, so IMNSHO it barely
even qualifies to be considered a "tiny BASIC".

The competing National Semiconductor INS8073 had 2.5K of ROM, and
Intel 8052AH-BASIC had 8K, so they supported more features of BASIC.