Problems with 74HC165 of ST

[Carlos]

Hi everbody

I have connected the 32 outputs of one circuit to 4 PISO's to connect these outputs to a PIC16C745 into the digital inputs. The problem is that I have connected everything like the datasheet, but in the serial output of the PISO only exit the H data, only the firt data of the data chain, and the PISO preserve the data after 10 or 20 time the clock, or more.

What do you guys think which is the problem???

Thanks

Carlos

[Viking]

Hello Carlos

Can you post a schematic, this is otherwise going to be almost impossible to diagnose. To add attachments (if you haven’t already done so), set your
Board Style to FI Subsilver Shadow in your profile. This will bring up an 'Add image to post' option just below the message dialog box

Regards
Rob

[rshayes]

It sounds like the PISO chips are not being shifted. In one form, these chips will require two control signals. The first signal transfers the parallel data from the input terminals of the PISO chip to an internal shift register (possibly called "load", "set", "preset", or someting similar). The second signal shifts the shift register to the out pin one bit per pulse (possibly called "clock", "shift", etc.). Eights pulses will be required to completely empty the shift register. Normally these two signals would be outputs from the PIC and would have to be programmed.