A standard 5 X 8 scrolling LED display typically has 8 rows of maybe 60
or more LEDs per row. A single bank of shift registers followed by
darlington drivers is connected to the cathodes of the LED columns. The
LED rows are driven by 8 PNP darlington transistors (high-side drivers).
The dot pattern is shifted into the shift registers, and strobed to the
output latches, and this process overlaps the display of the previous
(latched) row. Each row is displayed for about 10mS. High-brightness
LEDs (1000mCd or more) are recommended. Some designs pulse the LEDs at
high currents. I recommend running them around 20mA each, otherwise
intermittent LED and driver failures are likely to occur. The software
is quite intricate to design, I can assure you.

Lightbulbs are driven in a similar way but respond more slowly, of
course, and should have pre-heat current applied even when nominally
off, to avoid thermal shock from destroying the bulb.

> ----------
> From:         tpow@eramp.net[SMTP:tpow@eramp.net] on behalf of Troy
> Powledge[SMTP:tpow@ERAMP.NET]
> Reply To:     pic microcontroller discussion list
> Sent:         Monday, December 01, 1997 8:34 AM
> To:   'pic microcontroller discussion list'
> Subject:      RE: Scoreboard
>
> Are we talking about the type of score boards that you see outside of
> banks that display time and temp with light bulbs for pixels? If so I
> would like to know how all of the individual pixels are controlled.
> They have to be multiplexed some how. Any information about the system
> would be appreciated.
> Processor?
> Multiplex scheme?
> Software?
> Thanks,
> Troy Powledge
> TCo. Systems
>
>       -----Original Message-----
>       From:   Andy Tucker [SMTP:rtucker@SCCI.NET]
>       Sent:   Friday, November 21, 1997 7:42 AM
>       To:     PICLIST@MITVMA.MIT.EDU
>       Subject:        Scoreboard
>
>       I am looking for the person wanting some information on
> scoreboards
>       I have located someone who maintanes the sysyems in our county
> and
>       he said he would like to help.
>
>       Please E-mail me at rtucker@scci.net
>
>       Andy Tucker
>
>