Re: [lcd4linux] GPO circuitry

[Aragon G. <ar...@ph...>]

| By Aragon Gouveia <ar...@ph...>
|                                          [ 2004-02-15 19:42 +0200 ]
> Pretty sure.  For the backlight trick, each of the 16 outputs is connected
> to a resistor of different value (after going through a diode to prevent
> pull-down).  The output of each resistor is connected to the base of a
> transistor (I'm thinking 2N2222).  The output that is switched on will
> determine which resistor power flows through onto the transistor's base
> (thus providing a variable current level at the transistor's collector where
> the load (LED) will be connected).

Incase I'm introducing ambiguity, I will have 16 resistors, the output of
all of them will be connected to the base of a single transistor.  I wasn't
clear on that in my explanation.


Regards,
Aragon