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74hc595

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sajitmon

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sir , iwant to make an led matrix display ,in order to drive the columns iwould like to use 74hc595 shift registers ,can you help me with some sample circuit and programs?
 
sajitmon said:
sir , iwant to make an led matrix display ,in order to drive the columns iwould like to use 74hc595 shift registers ,can you help me with some sample circuit and programs?

How big a matrix?

D.
 
led display

thank you sir,i would like to use 7*5 led matrix.there will be 15 such matrices to display 15 characters at a time
 
sajitmon said:
thank you sir,i would like to use 7*5 led matrix.there will be 15 such matrices to display 15 characters at a time

You would need 7. But I would recommend using 6 74ABT574s, byte serial, with the last one driving 2 74HC138s driving transistors to the columns for a 40x16 physical matrix.

The ABTs can sink 100mA allowing you to run 7mA on each LED while the column transistors supply 250mA.

A National MM5450 would put out twice as much if you have an external 3V supply but then you have to bit-bang at a continuous 50KHz rate just to light the display ( 7*5*15*100 )

D.
 
sajitmon said:
sir , iwant to make an led matrix display ,in order to drive the columns iwould like to use 74hc595 shift registers ,can you help me with some sample circuit and programs?

And the MM5450 is $4 each
 
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