usb/input issues

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Re: usb/input issues

Postby dmitri » Sat Jun 07, 2008 8:45 pm

xploited wrote:32 and 10 is 17.8 ohm
32 and 31 is 5.2 ohm
30 and 31 is 9.8 ohm

Are you sure you're measuring it in the PCB's socket WITHOUT Atmega in it?
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Re: usb/input issues

Postby xploited » Sat Jun 07, 2008 8:53 pm

I just triple checked the datasheet to make sure I was touching the right pins.

To quadruple check... that pin layout is

1|---|40
2| |39
3| |38
4| |37
5| |36
. | |.
. | |.


right?

and yes, 100%, the pic is out. no power to the board either.
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Re: usb/input issues

Postby dmitri » Sat Jun 07, 2008 9:01 pm

Ok.
Now look at Synthex's schematic for PCB v2.7.
The only way to get from pin 32 to pin 10 is via R3 and L1. I.e 4k7 + 22R, far from 17.8R you measured.
The only way to get from pin 32 to pin 31 is via R4. I.e 4k7, far from 15.2R you measured.

Now can you tell me how it could be if you have correct R3 and R4 and no shortcircuits between these pins?
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Re: usb/input issues

Postby xploited » Sat Jun 07, 2008 9:13 pm

Wow... might I suggest to anyone reading this NEVER EVER EVER order from futurlec....

After really taking a look at the 4.7k resistors I bought from futurlec I noticed there actually 4.7 ohm. So there are actually quite a few resistors on there as 4.7 ohm instead of 4.7k.

Thankfully I have 10 actual 4.7k's kicking around from another project. Going to go ahead and change them up.

Should my atmega's work at that point? or would having those resistor values wrong hurt it?


I just want to say thank a million for the help!!! I've never donated to a project before really but come pay day I'll surely send you a little appreciation.

Thanks again!!!
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Re: usb/input issues

Postby dmitri » Sat Jun 07, 2008 9:21 pm

xploited wrote:Should my atmega's work at that point? or would having those resistor values wrong hurt it?

The one which has 9.6R between pins 31 and 30 is definitely hurt.
The one which has several MOhm between these pins might still be ok.

Check all other resistors. I personally always test at least one resistor from the same pack with a tester before using it. Mostly because cannot really read coloured rings' code on them:)
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