Serial communication problem upon soldering - Electronic Circuits Projects Diagrams Free

cimulation · 5th July 2009, 05:13 AM

I am trying to make a circuitboard for my circuit which is prototyped on the breadboard.

There are serial port Tx and Rx pins from a PIC16f688 which i use to interface to the PC. On the breadboard these work fine, when i soldered these onto my board the trasmission has a lot of errors. I have checked the connections and I am using wires to solder these onto the board.

Is there a recommended way of soldering when a serial transmission is concernced. What can be done to prevent these errors.

Best Regards and TIA.
Sumit

blueroomelectronics · 5th July 2009, 05:31 AM

You need a level converter like a MAX232.

cimulation · 5th July 2009, 03:56 PM

Quote:

Originally Posted by blueroomelectronics

You need a level converter like a MAX232.

It is something else. The ciruit works on the breadboard. There is some issue when i use solder in the same connection...

I suspect the issue with using a wire connection to connect between for the red and green connects.

AtomSoft · 5th July 2009, 09:44 PM

it has nothing to do with the soldering, unless its not right like the solder isnt making contact well or there is too much flux or you crossed traces or may a wire is melted somewhere and touching something eles

be80be · 6th July 2009, 02:25 AM

Quote:

I am trying to make a circuitboard for my circuit which is prototyped on the breadboard.

There are serial port Tx and Rx pins from a PIC16f688 which i use to interface to the PC. On the breadboard these work fine, when i soldered these onto my board the trasmission has a lot of errors. I have checked the connections and I am using wires to solder these onto the board.

Is there a recommended way of soldering when a serial transmission is concernced. What can be done to prevent these errors.

So it works on the solderless bread board with out a max 232 right?
If it did then it was the capacitance of the board would be the only thing that could of changed if you made the circuit the same. But you need a level converter a max232 would be the easy way to go.

BeeBop · 7th July 2009, 06:36 AM

If you wired a PC serial port Tx to the PICs Rx without a level converter you may have fried your PIC. + or - ~10 volts on a pic pin

Check the data sheet!

You haven't stated that you are using a level converter, and the diagram does not show one.

be80be · 7th July 2009, 06:53 AM

If he has a newer computer the voltage level may be lower some newer ones use the same
power that the usb uses. But I was thinking the same thing He may have cooked it.

geko · 7th July 2009, 09:53 AM

The output from the PICs UART is postive logic, i.e. 1==high, 0==low.

RS232 uses negative logic where a 1 is low and a 0 is high so even if the voltage levels were being detected as high and low, the data itself would be inverted including the stop and start bits.

We are of course making the assumption it's connected to an RS232 serial port. The O/P hasn't explicitly stated that is the case, only that it's connected to a PC.

Mr RB · 7th July 2009, 10:20 AM

PC RS232 ports have a fairly high output impedance, typically about 330 ohms. They will tolerate indefinite short circuits.

Connected direct to a PIC pin it would have pushed the PIC internal port diodes to about 30mA, not recommended of course but it's very unlikely to have blown the PIC.

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5th July 2009, 05:13 AM	#1
cimulation	Serial communication problem upon soldering I am trying to make a circuitboard for my circuit which is prototyped on the breadboard. There are serial port Tx and Rx pins from a PIC16f688 which i use to interface to the PC. On the breadboard these work fine, when i soldered these onto my board the trasmission has a lot of errors. I have checked the connections and I am using wires to solder these onto the board. Is there a recommended way of soldering when a serial transmission is concernced. What can be done to prevent these errors. Best Regards and TIA. Sumit

5th July 2009, 05:31 AM	#2
blueroomelectronics	You need a level converter like a MAX232. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com/

5th July 2009, 09:44 PM	#4
AtomSoft	it has nothing to do with the soldering, unless its not right like the solder isnt making contact well or there is too much flux or you crossed traces or may a wire is melted somewhere and touching something eles __________________ AtomSofts eBay Store AtomSoftTech: C18 TIPS & TRICKS v9 PDF My Name: Jason Lopez http://atomsofttech.info/ \| My YouTube Videos! My Favorite Store: dipmicro Electronics

7th July 2009, 06:36 AM	#6
BeeBop	If you wired a PC serial port Tx to the PICs Rx without a level converter you may have fried your PIC. + or - ~10 volts on a pic pin Check the data sheet! You haven't stated that you are using a level converter, and the diagram does not show one.

7th July 2009, 06:53 AM	#7
be80be	If he has a newer computer the voltage level may be lower some newer ones use the same power that the usb uses. But I was thinking the same thing He may have cooked it. __________________ Burt http://mybe80be.com http://stores.shop.ebay.com/mybe80be__W0QQ_armrsZ1

7th July 2009, 09:53 AM	#8
geko	The output from the PICs UART is postive logic, i.e. 1==high, 0==low. RS232 uses negative logic where a 1 is low and a 0 is high so even if the voltage levels were being detected as high and low, the data itself would be inverted including the stop and start bits. We are of course making the assumption it's connected to an RS232 serial port. The O/P hasn't explicitly stated that is the case, only that it's connected to a PC. __________________ Pete picprojects.org.uk

7th July 2009, 10:20 AM	#9
Mr RB	PC RS232 ports have a fairly high output impedance, typically about 330 ohms. They will tolerate indefinite short circuits. Connected direct to a PIC pin it would have pushed the PIC internal port diodes to about 30mA, not recommended of course but it's very unlikely to have blown the PIC.