Date: 8 Jul 82 1:00:01-PDT (Thu)
To: info-micro at mit-ai
From: decvax!harpo!duke!ucf-cs!goldfarb at Berkeley
Subject: H-8 Upgrades

I have an H-8 with 128K of memory, a Z80A, an S-100 disk controller,
and some other goodies.  It runs CP/M on normal, 8" floppies (Shugart
851's).  D-G Electronic Developments Co., 1827 S. Armstrong St.,
Garland, TX. 75020, supplied the CPU, replacement front-panel EPROM,
and the dynamic RAM.  Their prices were quite reasonable, as were their
designs, enabling the old H-8 to use the Z80A and all 64K of address
space at 4Mhz.  The disk controller is an S-100 type, a Jade Double D
purchased from Jade Computer Products in California for $60 for the
bare board.  It has an on-board Z80A and uses a WD 179X FDC chip.  I
made an adapter card to create an S-100 bus slot for the H-8.  This
required only two bus buffers and five other IC's, plus a slight mod
to the memory cards to handle the S-100 PHANTOM* signal.  Since the
Jade controller does not use DMA, no fancy interfacing was necessary.
With the above configuration plus a Heath 4-port serial card, the old
H-8 is a reasonable CP/M machine.  But don't count on Heath (or anyone
else's) support for too long:  the H-8 is dead!
				Ben Goldfarb
				USENET:   ...!duke!ucf-cs!goldfarb
                                ARPANET:  Goldfarb.ucf-cs @ UDel-Relay
