GIBSON RJ wrote:
>
> For my final year degree project I am going to
> build an LED display matrix,capable of displaying
> moving messages. Some sort of Microprocessor
> system is needed to control the display matrix.
> Because of the multiplexing method that is going
> to be used to control the display,a fast PIC with
> the following facilities is required :-
>
> - plenty of I/O lines.
>
> - an A/D converter (as it's also going to be
>   connected to a temperature sensor).
>
> - Serial comms facilities to allow connection to
>   a PC via RS 232 serial port.
>
> - It must be capable of accessing external RAM as
>   this is where the binary patterns representing
>   the message will be stored.
>
> I would appreciate any recommendations on what
> type of PIC would be most suitable for this
> application.

Connecting displays in series :

Constant Current
   >--!>!-*-!>!-!>!-!>!-!>!-*-!>!-->
          !                 !
           +   for LED's   -

When more is in series, then voltage is higher and the current is same.


Regards,
Jens Dyekjfr Madsen