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From: mbc@okstate.UUCP (Michael Carter)
Newsgroups: comp.sys.tandy
Subject: Re: XLER8 Boards
Message-ID: <1193@okstate.UUCP>
Date: Fri, 12-Dec-86 20:48:05 EST
Article-I.D.: okstate.1193
Posted: Fri Dec 12 20:48:05 1986
Date-Received: Mon, 15-Dec-86 20:18:39 EST
References: <7682@topaz.RUTGERS.EDU>
Organization: Oklahoma State Univ., Stillwater
Lines: 67

> 
> 
>   Has anyone noticed in the recent issues of 80-Micro, there is
> a company that sells the XLER8 expansion board for Model IV
> owners?  If I'm right, this is the same computer from Steve
> Ciarcia's article in 9/85 BYTE magazine.  Has anyone out there
> purchased one yet?  What's it like?  There is a video graphics
> attachment recently made by Ciarcia and it's in 11/86 BYTE if
> you are interested.

     Well, I think I can give you a little more insight into this little jewel.
I wrote the TRSDOS 6.2 and LDOS 5.x support software for it, and was in on
its design, and debugging.

     The XLR8er is is a plug-in speedup board for the Model IV or 4(p), gate
array or non-gate array.  Installation consists simply of unplugging the Z80,
and plugging in the XLR8er -- NO CHAINSAW NEEDED!  The board is based on the
new Hitachi HD64180 uP, and runs at 6.144 MHz.  It has an additional 256K of
DRAM on board, and is bus compatible with Ciarcia's SB180.

Operating systems currently supported are:

1.  TRSDOS 6.x
2.  CPM
3.  ZCPR3
-- and very soon --
4.  LDOS 5.x

     There are several pieces of software provided for each operating system.
Below is a list of the programs provided for TRSDOS 6.x.  LDOS 5.x support
will be out very soon, and the programs are basically the same.

1.  FIXALL/FLT  -- A filter to insert memory wait states on keyboard accesses,
                   and make sure @VDCTL is not fooled by the new memory mapping.
2.  FIXBANK/CMD -- A new @BANK SVC driver that provides 10 bank capability.
                   (The extra 256K can be partitioned off into eight 32K banks.)
3.  SET180/CMD  -- A utility to allow the user to set the memory wait states,
                   I/O wait states, and number of clock cycles between dynamic
                   RAM refresh periods.
4.  RAMDISK/DCT -- A new memory disk driver.  This new driver will allow
                   memory disk drives of up to 320K.
5.  BANKSTAT/CMD - Prints out the status of the ten memory banks -- reserved or
                   free.
6.  DISAS/CMD   -- A simple disassembler that will disassemble the extended
                   64180 instruction set.

     Program number 1's raison d'etre is that some Model IV's keyboard
hardware cannot handle zero memory wait states.  This program provides
a simple, transparent fix to this problem.

     I have been running my XLR8er (or Superchicken as it is called internally)
for about a year now, and it hasn't had glitch one yet.  With the increased
clock speed, and the better efficiency of the 64180, CPU throughput is
increased up to 100%

     If you have any more questions about the XLR8er, please feel free to
post more articles on the net, or mail me at my electronic address.

Michael Carter
Department of Electrical and Computer Engineering
Oklahoma State University

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-- 
Michael Carter