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Topic: Stupid schematics (Read 924 times) previous topic - next topic

thegoodhen

Jun 30, 2012, 05:43 pm Last Edit: Jun 30, 2012, 06:03 pm by thegoodhen Reason: 1
I just spent few hours nicely soldering together this circuit. http://arduino.cc/en/Tutorial/ShiftOut Now I realised that the pinout on the schematics doesn't correspond with actual chip pinout. ANGHHHTTT! ALL CAPS RAGE!!!! Yeah, so that's it. Feel free to learn from my fail.
EDIT: IF you know of any shiftreg with pin layout that corresponds with the one shown on aforementioned link, I'd be more than glad.

johnwasser

You'll find that many schematics group chip pins together by function and not by physical location on the chip.  Often it is clear that is what they are doing because you will have pins on three sides or more pins on one side than another.  Just your luck that the schematic shows 8 pins on each side, just like on the chip.  If you have the chip in some kind of perf board you can move it down a notch to get Q1-Q7 in the right places.

Next time it would be good to prototype the circuit on a breadboard before soldering everything together. :(
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thegoodhen

Quote
Often it is clear that is what they are doing because you will have pins on three sides or more pins on one side than another. 
Unfortunately this wasn't the case. Also-I just quickly checked the pin layout displayed on top with the schematics-And because of the pins at the left side, they looked the same. Yeah, but thanks anyways. I might be able to repurpose some of the soldering, but I seem to be running out of the soldering iron. Wish me luck. :D

thegoodhen

OK, I've done it finally. I found the lead-suckin-wire-thingy, so it wasn't that difficult after all. :D

Grumpy_Mike

Did you put that capacitor on the latch pin?
If so take it off it will damage the arduino.
Lots of people have been trying to get them to change it but to no avail.

CrossRoads

I've sent an e-mail to massimo banzi & david cuartielles, will let you know if they respond Mike.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Graynomad

#6
Jul 01, 2012, 03:25 am Last Edit: Jul 01, 2012, 03:26 am by Graynomad Reason: 1
The pinout of that SR is clearly shown but I admit the schematic could be a bit confusing for a beginner. Regardless it should have pin numbers on the schematic, without them it's really just a block diagram.

Quote
I've sent an e-mail to massimo banzi & david cuartielles

After all this time and probably a 1000 people using that stupid cap and another 1000 people highlighting the error, good luck :)

Still it's possible that despite that nobody has actually emailed them after all this time because we assumed the problem would be noticed.

This is probably one of the most popular playground pages, every man and his dog uses it when first playing with shiftOut(), and it has a bad error.

It should be fixed.

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

CrossRoads

That was actually my first time looking at it.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

thegoodhen

Hi there, I couldn't find the capacitor, so I didn't put it there, it didn't seem to serve any purpose, anyway. Furthermore, wouldn't this cause the cap to blast voltage back into the poor duino? O_o.

Grumpy_Mike

Sort of, it causes excess current to flow both out of and into the arduino. It should be across the power pins of the chip to act as supply decoupling.

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