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Topic: Incorrect schematic (Read 809 times) previous topic - next topic

beerbarrel

Don't know if you guys are aware of this but if you go to the shift register page the first schematic does not agree with its diagram above it. The diagram seems to be correct but not the schematic.

Tracy

Graynomad

Link?

I can never find anything on the reference/playground pages.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

beerbarrel

http://www.arduino.cc/en/Tutorial/ShiftOut

If you take a look at the third diagram down there is a schematic below it that shows how to wire up the diodes. The schematic and the diagram do not jive. The diagram is correct. I tried wiring them like the schematic and the circuit does not work. I could be missing something though. :)

GaryP

Could you show us the difference, it might help. I am planning to do that, it would be nice to find problems before testing.

I can't find what is wrong.

Cheers,
Kari
The only law for me; Ohms Law: U=R*I       P=U*I
Note to self: "Damn! Why don't you just fix it!!!"

Graynomad

At a glance I can't see the problem but that's a bad schematic because it doesn't have any pin numbers and I don't have time to go looking for a 595 data sheet.

This schematic is notorious though for the addition of a cap on the latch pin, we've been asking for that to be removed for years but it seems that all requests for doco changes fall on deaf ears.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

floresta

#5
Jan 04, 2012, 03:53 pm Last Edit: Jan 04, 2012, 03:58 pm by floresta Reason: 1

Don't know if you guys are aware of this but if you go to the shift register page the first schematic does not agree with its diagram above it. The diagram seems to be correct but not the schematic.


Tracy:
The diagram and the schematic aren't correct, as mentioned by Garynomad, but they do agree.  My guess is that you think that the pin locations on the schematic diagram of an IC should be physically the same as the pin locations on the chip itself.  That is absolutely incorrect in spite of the fact that many so called 'schematic' diagrams on this and other sites are depicted that way.  On a true schematic diagram the pins are positioned in order for the signal flow to be as straightforward as possible, typically left to right and/or top to bottom.  


Don

beerbarrel

OK..I see where I was going wrong. The schematic pin config is laid out different. Seems it should have been laid out like the data sheet. I guess that is what I get for assuming. Thanks for the clarification.

Tracy





Graynomad

#7
Jan 04, 2012, 10:01 pm Last Edit: Jan 04, 2012, 10:02 pm by Graynomad Reason: 1
IMO this schematic is the worst of both worlds, it's drawn as though the pins are the same as the chip, placed directly below a physical diagram, in an article that's designed for beginners, and yet the pins aren't in the same location as the chip and there are no pin numbers to help. Not appropriate for a beginner tutorial.

It's very misleading and I can see why you were confused.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

floresta

Quote
IMO this schematic is the worst of both worlds,

And unfortunately it looks as if we are stuck with it until the end of time.

Don

ajofscott

The cap should have been small like 0.001uf and been tied to the register clear pin with a 1k pullup so that the registers are 0'd prior to accepting incoming data.

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