INTERNAL LAYOUT

Description-  This next evolution of the original IMSAI 8080 Microcomputer System offers outstanding features and capabilities for hobbyists, students, software and system developers, and anyone else wishing to develop 8-bit applications and hardware.  The IMSAI SERIES TWO utilizes the powerhouse 50 MHz. Zilog eZ80® Acclaim! microprocessor and provides a complete system on two IEEE-696 compatible S-100 boards including:

MPU-C System Board-
Recent experience with an advanced Zilog processor module has allowed us to incorporate this technology into the S-100 bus MPU-C processor board.  The eZ80® is revolutionizing the high-performance MPU market for today’s 8-bit embedded applications. The eZ80® executes Z80 code four times faster than traditional Z80s at the same clock speed, and can operate at speeds up to 50MHz. Unlike most 8-bit MPUs, which can only address 64KB, the eZ80® can address 16MB without a Memory Management Unit. The eZ80® also supports demanding TCP/IP networking applications, featuring an Embedded Internet protocol stack that enables the transmission of HTML form data and the dynamic generation of web pages, and supports additional higher-level networking functions such as email and SNMP.

 The MPU-C processor board has it's own Lattice Semiconductor ispM4A5-128/64 CPLD which is a reprogrammable logic device configured to provide the majority of interconnect "glue logic".  Use of this part allows the user to reconfigure the board resources for specific applications and unique requirements when using Lattice's ispLEVER Basic or Advance development kit.  We provide full source code and user guides to assist in changes to the board architecture and I/O.

Programmers Front Panel Features-  The "USB" front panel is very similar in look and feel (almost identical, save a few labeling changes) to the original IMSAI CP-A.  The main difference is that the front panel hardware is controlled by an on-board microcontroller which happens to have a USB interface.  Use of the USB interface is optional. 

The USB microcontroller is responsible for "scanning" the front panel switches, and illuminating the LEDs.  The communication with the eZ80 is done through the Zilog Debug Interface (ZDI) which is a serial interface similar to i2c.  Using ZDI allows the front panel much greater capability in controlling the CPU without adding extra complexity and cabling requirements to the hardware. 

In addition to examining/depositing memory, single-stepping, etc, the new USB front
panel can also examine/deposit eZ80 registers, I/O ports, set breakpoints, execute instructions, etc.  When connected to a PC via USB (and with the proper software and drivers on the PC) it will be possible to "download" code to the Series Two via USB through the ZDI interface.

We're also looking at the possibility of integrating the USB front panel with Zilog's integrated development environment and graphical debugger.  While this is fairly straightforward from a technical perspective, it will require some relationship with Zilog that we haven't yet developed as yet.

The USB front panel can also be used "stand alone" without a real eZ80 processor, by using a PC to emulate the target hardware.  In this case, the USB front panel adds the "lights and switches" to the emulated system.

Board power is provided by a PC ATX-style switching supply that produces a safe UL/CSA-approved source of power superior to the original IMSAI power supply.  It also provides a convenient source of power for conventional floppy and hard disk drives, as well as CD ROM drives as used in today's PC architecture.  Additionally, the power supply supports the remote power ON/OFF feature of the PC/ATX specification, and this feature is extended to the front panel.

The cabinet is modeled after the original IMSAI 8080, utilizing the same aluminum construction, familiar switch-and-LED layout, color, and finish as its predecessor.   Most metal parts and the front panel are interchangeable with original IMSAI 8080 cabinets, ensuring an upward path of enhancement for owners of older IMSAI's.

Motherboard-  The IMSAI Series Two is provided with a 9-slot actively terminated IEEE-696 compatible motherboard loaded with 9 high quality S-100 board sockets.  An optional 20-slot actively-terminated motherboard is also available, although it's use precludes installation of an optional ATX-style motherboard.  See our ordering information table for for further details.  The IMSAI Series Two system design allows operation up to, and exceeding 10 MHz. with no wait states, depending on capabilities of user-supplied accessories.  Programmable wait states allow use with slower S-100 boards and peripherals.

What you need to complete the system:

If the user chooses to mount an ATX motherboard, a "download" cable may be connected between the IMSAI Series Two parallel port and the corresponding ATX motherboard port.  We will provide CP/M operating system support including a CBIOS driver on the IMSAI Series Two side that accesses the ATX parallel port as if it were a disk drive.  The PC software support includes a small software "server" that uses the native DOS/Windows or Linux operating system to manage files.  This way, it becomes very easy to transfer programs from the web and run them on the IMSAI Series Two.  It's now easy to transfer files from native IMSAI and CP/M-compatible disks (i.e. to convert files from 8" or 5.25") and store them on your PC. 

IMSAI products are shipped factory assembled and supplied with a no-hassle two-year warranty on parts and labor UNLESS specified otherwise.  See the warranty details on our ORDER page.