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faizanbrohi

Parallel Port LED Dimmer.

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I am Planning to build a parallel port led dimmer using ti's TLC5904 which uses 8 data inputs for adjusting the brightness or in other words current . you can control upto 15 LED's using this IC .

I know how to interface the parallel port But there is some complication in this is , i don't understand what is a DOUT For , DIN DCLK are used for input for brighness control , and there input will come from a parallel port , since a parallel port is a 8 bit ouput from a computer  . i don't know why dclk is for , do i have give external clock pulse . here is the ic pinout

tlc5904.pdf

post-15126-14279143117278_thumb.jpg

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okay 33 pins are NC which are not connected so this leaves only 67 , out of which 16 are output to led which leaves 51 pins out of which 16 are for DIN and DOUT which leaves 35 pins and out of which only 2 pins are for register select for brightness control and DCLK , the only question i want to ask is that the maximum rating of DCLK is 15Mhz and there is no min or typical value given , so since 15Mhz is maximum so i can drive it with a 1Mhz clock refrence using Timer TLC552 . That is the only question please helppp....

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The data sheet is here:
http://focus.ti.com/lit/ds/symlink/tlc5904.pdf
The answers to your questions are in the datasheet. Dout is described somewhere around page 17.
1MHZ clock should be ok. It will just transfer data much slower.

MP

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