Using a 74HC595 serial/parallel register with a single clock

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quintosardo

Joined: 03 Jul 2006
Posts: 4

03 Jul 2006 10:43 Using a 74HC595 serial/parallel register with a single clock

Hi,
did anybody try to use a 74HC595 connecting together the shift and the latch clock to use only two wires (data and clocks)?
I'm trying to do this but I have strange results until the chip gets locked (the output doesn't change).

Any suggestion?

Thanks

Quinto

Attila_ati

Joined: 04 Jul 2006
Posts: 2

04 Jul 2006 13:09 Using a 74HC595 serial/parallel register with a single clock

Hi
To run 74HC595 you must have at least 3 wires that includes serial data input,latch and shift.Unfortunately 74HC595 doesnt run properly with two wires.My advise that;dont forget to add third wire(serial data input) good luck;-)

kisudu

Joined: 16 May 2006
Posts: 18

05 Jul 2006 9:30 Re: Using a 74HC595 serial/parallel register with a single c

Beacause of above reasons, you should use 4094, that meet your demand.
Good luck,

Last edited by kisudu on 06 Jul 2006 16:05; edited 2 times in total

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quintosardo

Joined: 03 Jul 2006
Posts: 4

05 Jul 2006 9:32 Re: Using a 74HC595 serial/parallel register with a single c

I've solved the problem.
There was a bug in communication code.

Now I can drive the 595 with those 2 wires:

- serial data input
- shift and latch clocks tied together

I had to add one more clock up/dw because, as the datasheet says, latch clock is one step behind the shift clock, when tied together