Anonymous User
PowerComm card testing
June 07, 2007 09:05AM
Hi all,

My flat look like a geek cavern today, opened computer on the sofa (to power the card) and electronic workshop on the kitchen table for soldering smiling smiley

I've question about PowerComm testing.
Because echo is not working properly when trying from console, I've take my multimeter to test pins as described on []

During first run (no comm, no module connector), the only mismatch is:
Pin 15 to 11: 4 to 4.5V but I get 0v

I think it would be normal as no module connector cable is plugged on pin 11.
Could someone tell me why there's a mismatch?

Re: PowerComm card testing
June 07, 2007 08:28PM
Make sure you know how to test at the comport itself. You should be able to get characters to echo when you short rx to tx. If you can't do that you don't have things configured right. If you can then you and follow the tx on the serial through the converter to your pic, again shorting rx to tx at output of max232 should look the same. if that's ok, then its all about getting the pic wired right.
Re: PowerComm card testing
June 08, 2007 02:22PM
> if that's ok, then its all about getting the pic wired right

??? There is no PIC on a PowerComms board, is there?

Re: PowerComm card testing
June 08, 2007 04:06PM
also, double check to make sure you have the molex connector on right... the notches should face bottom/outside the board. the silkscreen is WRONG! sorry.
Anonymous User
Re: PowerComm card testing
June 08, 2007 07:13PM
Yes, forgot about the molex connector on first try, but changed its side to make the LED working. Could a first electrical try with molex on wrong side burn some componants? (no smoke yet, so should be ok)

About the PIC, is it the max232? it seems to be wired correctly.
The card is not echoing the characters I enter in console (with parameters given on wiki), so I checked values with multimeter and some a wrong (like the pin 15->11: 0V on mine, 4.5V on wiki)
Re: PowerComm card testing
June 08, 2007 07:51PM
nonono, pic is 16f628a, the comm chip is the max232.
Did you check that rx shorted to tx at rs232 port itself works?
You don't need the pic until after you know you have comm stuff working.
If you don't set up right parameters on comm software, it won't work.
Look back a couple posts to my previous.
Anonymous User
Re: PowerComm card testing
June 08, 2007 09:59PM
For clarification's sake (I was confused a bit by this when I was troubleshooting my boards), first you check the serial port itself by keeping the serial cable plugged in to the PC, and unplugged from the power/comms board, and shorting across (carefully!) the TxD and RxD pins of the end of your serial cable (you can identify the pins on a diagram on this page: [] ). In your terminal software (such as hyperterminal, minicom, etc), with character echo turned OFF, you should see any character you type into the terminal software appear in the terminal window. As soon as you stop shorting those pins, any letter you type should NOT appear in the window. Once you have verified that this works, connect the serial cable to the power/comms board (leaving it connected to the PC), with the MAX232 chip in the board, and look for the two pairs of pins marked GT and GR on the board. Connect T and R together (you can ignore the Gs), and anything you type in the terminal software should appear in the window, and with T and R disconnected, whatever you type will NOT appear in the window.

If this works OK, then you have basic communications with the board.

I am not sure why it says that there should be 4.5v between pins 15 and 11 on the Power/Comms board... Pin 15 is attached to the negative from the main power connector, and pin 11 is attached to the R connector. Without any boards attached to the Power/Comms board, I don't see how there can be any voltage there. I think that part of the page is from an older version of the board. Zach, or anyone with circuit board knowledge, can you please go through those tests and make sure they are correct?

Hopefully this helps you out, Alexandre.
Anonymous User
Re: PowerComm card testing
June 09, 2007 07:30AM
Thanks for your help Bartlee and Eric, I've been able to understand how it works now.

In fact, I was expecting a double echo of what I typed in the terminal window, not knowing the single echo was meaning it was already working smiling smiley

Hope this thread will help new comers in the future.
Re: PowerComm card testing
June 09, 2007 04:55PM
yay! i'm glad you got it working. no doubt this will help someone with the same question in the future.
Re: PowerComm card testing
June 09, 2007 05:02PM
with the new setup, you *CANNOT* break things by soldering in the molex connector backwards. the worst that you can do is send 5V down the 12V line which just means things dont get enough juice to work properly.

now, if you were using the old board version like i was... then you may or may not have ended up with a fried computer angry smiley
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