Date   : Mon, 01 Dec 2008 23:43:22 -0000
From   : mfirth@... (Michael Firth)
Subject: OT (-ish): Beeb meetup at BYTE BACK? (March 2009,

Sounds like a case of 'great minds think alike' (or maybe 'fools seldom 
differ'!)

While at school I built an 8x8 matrix of LEDs that connected to the user 
port. It used one of the control lines on a write to increment a 3 bit 
counter, and then a 3 to 8 line decoder to select which row of LEDs to 
address.

A small bit of machine code running of the 50Hz interrupt then effectively 
memory mapped all the LEDs into 8 bytes of memory, so fancy patterns could 
be created from BASIC programs just by writing the correct values to the 8 
locations.

Mine only had one of the standard plastic project boxes - drilling the 64 
holes was a real pain, and they weren't quite aligned, but not too bad.

It still worked when I fired it up a couple of months ago, I was mainly 
using it to test the user port on my Beeb.

The slightly more ambitious plan that my friend back then had of building an 
8x8 disco bulb matrix with a load of TRIACs etc to generate a large 
mains-powered compatible version, never got very far though...

Michael

----- Original Message ----- 
From: "Rob" <robert@...>
To: "BBC micro mailing list" <bbc-micro@...>
Sent: Sunday, November 30, 2008 8:26 PM
Subject: Re: [BBC-Micro] OT (-ish): Beeb meetup at BYTE BACK? (March 
2009,Stoke UK)


> OK, tickets booked :-)
>
> About the only thing I can think of that I've got that is 'unusual'
> which would be worth bringing along would be a 8x7 LED display that I
> built as a project while as an apprentice at Ferranti in, um, 1992 or
> so.  Adapted from a magazine design, it nevertheless worked quite
> nicely, and looked good in a black poweder-coated box (which I had to
> fabricate as well).  Simple 8-bit conection to the user port, and it
> used shift registers to hold the display.  I think I know where the
> box is, but finding the software may be an issue...  not that I
> couldn't recreate it, but I had some nifty patterns and animations
> coded up at the time.
>
> Anyway, hope to see you all there...
>
> Rob
>
>
> 2008/11/29 Rob <robert@...>:
>> Remarkably, the family are interested in going too (although more for
>> the gaming side methinks), so it's posible we'll be there.  I just
>> need to clarify some access issues, which I've sent a message about,
>> so we're awaiting a response before we book.
>>
>> Rob
>>
>> 2008/11/29 Alex Taylor <zeem.uk@...>:
>>> 2008/11/29 Ian Wolstenholme <bbcmailinglist@...>:
>>>> I would be interested in this, it's about time I turned up at 
>>>> something!  Is anyone
>>>> else planning to go?
>>>>
>>>
>>> I'm certainly interested. Stoke's not too far from here, and it looks
>>> like there will be some interesting stuff there.
>>>
>>>
>>> --
>>> Alex Taylor
>>>
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>>
>
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