Hey, this might be a simple fix, but I'm at my wit's end. I was following the 'ShiftOut' tutorial on this site and I'm not sure what's gone wrong.
On the HelloWorld example in stead of counting in binary up to 255 the output is simply blinking the bits in the 1's, 64's and 128's place. (with the last two bits much weaker than the first)
I changed the code to just hold the number 255 to troubleshoot. When I used my DMM I found that the voltage across the LEDs are as follows:
Still only places 1, 64 and 128 are lit. I have tried reversing the polarity on the LEDs and they are all oriented the same. has anyone had this issue when trying this tutorial or have any suggestions as to what to try?
my specific chip is the Texas Instruments sn74ch595n if that matters.
The shift register tutorial on this site has some long-standing errors.
One of them has been fixed recently.
The capacitor should be on the VCC pin, not on one of the data pins.
The schematic view is now correct, but the breadboard view is still wrong.
Not sure if that has anything to do with the problem you're experiencing.
Are all the LEDs the same, and did you carefully inspect resistor values.
Measure the resistors with a DMM if you're not sure.
I did double check the resistors and they were correct. to be honest I just tore it apart and rebuilt it and now it's working (I used a 7-segment display instead of regular LEDs).
PaulRB:
So Wawa wasted his time replying to your question. How do you think that makes Wawa feel? Is he more or less likely to want to help you in future?
I think that is a bit harsh. Being a beginner, things are not always obvious. More experienced users might be able to easier track problems and if only if they don't succeed will go to forums for advise.