STP16DP05 ShiftOut Query

Hey everybody,

Okay, I've run into another problem with my new friend, the STP16DP05B1R 16-bit shift register.

I am following the ShiftOut tutorial, which tells me that for a sink driver such as the STP16DP05, I have to put the anodes of my LEDs to the common power line and connect the cathodes to the shift register outputs. I made sure to switch the line connecting the shift register board to the LED board from ground to positive. Everything seems to be plugged in properly. However, I am getting no response from the ShiftOut hello world.... :(

I have done a bit of sleuthing, and it would seem that the problem arises from the external resistor. I found a forum post here that says something to the effect of my problem:

Not the same board but similar concept. What does it mean to "connect between VDD and the I/O"? I know what VDD is and where it is on my chip, but which I/O is this person talking about? Does this mean that I need to resist all of my LEDs individually?

Thanks in advance for your help everyone.

My head hurts.

the comment:

"They're called LED sink driver (kinda open-drain output on PICs)... so you must connect between VDD and the I/O."

Is, as far as i see it about the LED's not the current limiting resistor.

Can you meassure any voltage on the output pins ?

Does this mean that I need to resist all of my LEDs individually?

YES all LEDs must have there own resistor.

MikMo: I am reading a constant 4.33 V out of pin0 while running the ShiftOut Hello World. It would appear that power is running. It's the strangest thing though, I went back to following the original instructions in the tutorial (without the anodes and cathodes flipped) and I am getting a really faint light out of my LEDs. It does not blink, it just remains constant. Have any ideas?

Mike: Hey again, pal. I thought that the whole point of a constant current IC was the eliminate having to resist each LED individually. Am I wrong?

Here's an image of my setup. I hope it helps. I can provide a higer res version if needed.

Oh dear lord.... okay. Brain fart, everyone. Mixed up data and clock pins. I need to get new glasses......

Go about your business.

Mike and MikMo: You two rock. I'll upload the project when I'm done. See you on the boards.

Hey, Do you still have the image – P1040362.jpg

I'm trying to get it to work on my end, and wanted to see the wiring.