Intersystems
Series II Z80 CPU Card.
This was Ithaca Audio's
(later known a Intersystems) second Z80 CPU card.
The card was designed
to be IEEE 696 compatible. The card was sold as a kit. It have an onboard
ROM allowing a monitor boot directly from the board. It also had on board
complete circuitry for an AMD 9519 interrupt controller.
However its most useful
feature was that the card could address 1Mg of RAM address space by programming
two onboard 4K "windows" through an IO port. This allowed the card to work well
with CPM3. The card was extremely reliable and worked up to and beyond 5MHz
on a properly terminated bus. For the card in the above picture I modified it, replacing
the normal crystal with a clock generator allowing a more stable clock and the ability
to easily change it.
The Intersystems Series
II Z-80 board was one of the first S-100 processor boards to take full advantage
of the IEEE specification,. It has many special features that made it
both powerful and easy to use.
Among these features were:-
S-100 bus cycle generator creates IEEE
standard bus cycle timing for all bus operations to guarantee compatibility
with all IEEE S-100 products.
A simple address management system
provides two 1 Kilobyte segments reloadable anywhere in the first megabyte of
the 16 megabytes of the S-100 address apace. Four light-emitting-diodes Indicate
the four most-significant address bits.
A Vectored Interrupt
Controller gives sophisticated, high
speed interrupt handling with individual
masking, fixed or rotating priorities,
and optional polled operation.
2 or 4 MHz processor speed
was on-board pin-jumper selectable.
PROM monitor socket will accept 2?08,
2716, 2759, or 2732 EPROM's and a reset jump is provided to the PROM.
The PROM may be addressed at
any 1 K boundary in the 64 K address space.
On-board wait generator optionally
adds a single wait state to any Instruction Fetch, Memory Reference, Input/Output
Reference, or on-board PROM Reference.
On-board circuit conducts the ISEE
specified nested bus transfer for glitch-free DMA operations, and DMA controllers
need not duplicate the circuit.
Operation without a front panel is
supported both by optional MWRT generation, and by a specially designed front-panel
connector which includes the Reset,
Jump Enable, and GND signals from the processor
card.
Special engineering features include
2 self-test modes for quick circuit debugging and Address and Status latching
to reduce bus noise and improve reliability.
The manual for this
card can be downloaded
here.
See here for more discussions about this
board.
Other InterSystems S-100 Boards
64K Dynamic RAM
8K RAM
EPROM
IA-Display
FDC
IO-Card
Z80-Series-II
Z80
FPB
256K Dynamic RAM
16-64K EPROM
HDA
Z80-Series_III
6SIO
EPROM Emulator
RTC Board
This page was last modified
on 01/08/2011