Anyone playing with the 8x300 - test-drb@ccmp.vtda.org

13 May 2005

...
 From: "Allison" <ajp166 at
bellatlantic.net>

Subject: Anyone playing with the 8x300
   From: "Dwight K. Elvey" <dwight.elvey at AMD.com>
   Date: Fri, 13 May 2005 14:29:31 -0700 (PDT)
     To: cctalk at classiccmp.org

Hi
 I'm looking at an application of the 8X300 by
Signetics. This is for a hard disk controller.
Is anyone fiddling with simmulators for this processor.
It seems like someone was a while back.
 My current application is on an Olivetti M20 not
a TRS80.
Dwight

Ah the classic first of the fast microcontrollers.
I'd have to dig but I vaguely remember the 8x300
as a disk controller apnote.  Nasty beast to program.

Allison

Hi
 Don't know why you'd say this, it only has 8 instructions!
I've got the spec posted to Al's site.
 This controller application is a little interesting in that 
who ever designed this board, also must have done a bitslice
designs at one time or another. To save a machine cycle, all
I/O addresses are selected by a ROM tied to the instruction
addressing. Normally it would take two cycles, one to write
the I/O address and one to transfer the data. With the
ROM, the address is understood by the program's execution
address location.
Dwight