Newsgroups: comp.robotics
Path: brunix!uunet!gatech!howland.reston.ans.net!zaphod.mps.ohio-state.edu!uunet.ca!geac!r-node!apollo
From: apollo@r-node.hub.org (Andrew P. Herdman)
Subject: Re: Anyone expanded a miniboard?
References: <1o2f3n$68u@horus.ap.mchp.sni.de>
Organization: R-node Public Access Unix - 1 416 249 5366
Date: Thu, 18 Mar 1993 00:32:27 GMT
Message-ID: <1993Mar18.003227.28967@r-node.hub.org>
Lines: 49

In article <1o2f3n$68u@horus.ap.mchp.sni.de> odwyer@sse.ie writes:
>I'm considering building a miniboard, and was wondering if anyone
>has ever expanded on the basic spec.
>
>Specifically, has anyone ever done any of the following:
>
>1)  Added RAM/EEPROM?   Can the 6811 handle this?  I assume that all that
>is required is the RAM/ROM ics and a decoder IC - is this correct?
>
Easy, you have to set the MODEA and MODEB pins add a 8-bit latch (most
hc11's have a multiplexed bus) and chip selects and your done.  I don't
have a miniboard but I think you'll have to build your own board for this.

>2)  Added a keyboard or a display?  I'd like to hook up an LCD display
>and a small keypad, but haven't a clue how to go about it.  I assume
>an LCD display would be memory mapped somehow (or does anyone sell a
>device which communicates serially), and I'd have to build some decoding 
>logic for that - is that all?  Will the power supply be adequate, or do I 
>need to do something else?  
>
A keyboard and display can be added using the fast serial connectors.
If you can program enough to simulate the I^2 bus, you can add a whole
bunch of stuff, from keyboards, display, memory, flash eeproms etc....

>3) Interfaced to a larger computer other than with the serial jacks?
>What are the electrical issues, if any, in connecting to the bus of another
>CPU?  The CPU is likely to be a 680x0 or 80x86 (far, far in the future...:)

You could add a scsi to a hc11, or any other bus specs (try to make it
8-bit for easy of use).
>
>I'd be grateful for any pointers from anyone who's done any of these 
>things before.  About me:  I've read the FAQ, got the miniboard docs,
>and have a reasonable knowedge of digital logic, and a very thin
>grasp of electronics (:-( ).
>
>Thanks in advance,
>
>Frank O'Dwyer
>odwyer@sse.ie   (please use this if emailing)


Andrew

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