[SOLVED] Shift Register Issue

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venkates2218

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Hai,This is my shift Register circuit.When the circuit powered up,the output which connected to the IC is switched ON for an moment.I tired this circuit also,but facing the same issue.
How to solve this issue.

I can't create an contineous tread with previous topic,so created an new one.
 

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Hi

Did you read the HC595 datasheet?
If so,
* why don't you use /OE?
* why don't you use /MR?
* you know that the clocks react on rising edges. And with a pull up you create counter productive rising edges.

The most safe way:
* use external pull down on outputs
* connect /MR to the /microcontroller_reset if possible, else pull high
* make /OE microcontroller controlled and use external pull up on /OE
after microcontroller_reset:
* initialize ports
* run command to load the HC595 with desired start up states
* make /OE = LOW

Klaus
 
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