S100 Computers

Home S-100 Boards History New Boards Software Boards For Sale
Forum Other Web Sites News Index    
Jade Computer Products -   JGZ80   Z80 CPU Board
The board had the advantage of being a late arrival to the S-100 bus so it was well enhanced with features.

JGZ80 Board

Jade called this board the "Big-Z".  It had on board a socket for a 2704/2708/2716/2532 EPROM which could be addressed on any 1K, 2K, or 4K boundary. There was power-on jump directly to on-board EPROM with optional wait states for the on-board EPROM.  The on-board EPROM could be used in shadow mode (access only after power-on or reset) allowing the full 64K RAM memory to be used. Automatic MEM WRITE generation if front panel was not used, disabled if front panel was connected. DMA Capability at 2 or 4 MHz operation.  Latched data output bus provided additional data hold time for reliable operation with all device types.  Straight-through address and data paths provide improved read access times for I/O and memory devices.  There was an on-board USART for synchronous or asynchronous RS232 operation. The connection was a 16 pin IC socket.  There also was a Baud rate generator on board to provide all standard baud rates. The USART could I be assigned to any group of four I/O addresses (only two are used). Finally, reverse channel capability on USART allows use with buffered peripherals or devices with  a "not-ready" indication. Interestingly a Clock 1 & 2 was generated with a 8224. This was not a an IEEE 696 type board. There was for example no memory addressing past 64K.
The manual for this board can be obtained here.


Other Jade S-100 Boards
Bus Probe    8K Static RAM   Z80 CPU   64K RAM   FDC   1P2S


This page was last modified on 10/25/2013