[RESOLVED] Pulse and serial outputs not working.

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bratan
Posts: 16
Joined: Fri Jan 04, 2013 4:02 pm

[RESOLVED] Pulse and serial outputs not working.

Post by bratan »

I finally got FTDI 3.3V adapter and setup XTerm as described, however I'm not getting any signal for Geiger counter on terminal program. Also tried with putty, it simply doesn't send anything to serial.
I suspect that PCB might not be labeled correctly. It says GND by the last pin (6), but when I tested with my DMM (from battery holder negative) it's not connected to ground, it seems that actually Pin1 and 2 are ground. Can you please verify?
Also I'm not getting anything from 3 pin pulse pins when hooked up to Geiger Bot. It might be because I used slightly different R values to reduce voltage (I'm using R1=10K and R2=220). Can you suggest how to measure signal from pulse pins? DMM doesn't register anything, do I need oscilloscope? :)
Last edited by bratan on Wed Jan 30, 2013 11:07 am, edited 1 time in total.

bratan
Posts: 16
Joined: Fri Jan 04, 2013 4:02 pm

Re: [PARTIALLY RESOLVED] Pulse and serial outputs not workin

Post by bratan »

Update:
Ok I was able to get Serial working. Just as I suspected PCB is labeled wrong, basically reversed. J7 jumper's left most pin (1) labeled with arrow is actually GND, and last one should be DTR (it's not connected anyway). So looks like schematic is correct but silkscreen is incorrect. Now I'm trying to figure out pulse part

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mightyohm
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Re: [PARTIALLY RESOLVED] Pulse and serial outputs not workin

Post by mightyohm »

Hello,

That label says "grn" as in "green", not ground. The FTDI cable has a green wire that goes in that position. Ground is on the "blk" or "black" side. Sorry.

You can't measure the PULSE output with a DMM unless it has a super fast response, and a scope would be super handy. Have you seen this post?
http://mightyohm.com/blog/2012/03/how-t ... r-counter/

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