0

Possibly fried 2 pins on Arduino? help!
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Possibly fried 2 pins on Arduino? help!

by johndavid400 on Mon May 11, 2009 1:46 pm

hello, I have been trying to decode a 6-signal PPM stream from an RC receiver through Arduino digital pin 8, which is supposedly the only pin on the arduino that can handle interrupts. I was prodding around with a wire attached to pin 8 whilst trying to locate the correct clock pin that sends out the PPM stream from the RC receiver. I tried touching several different contacts on the RC receiver and think I may have fried pin 8 on Arduino. Now when I try to use pin 8 for anything, just a simple 1 sec on/off pulse to test it, it has almost nothing. Every other pin gets 0-5v, pin 8 just barely moves the needle on my voltage meter and pin 7 reads between 1.5 - 3.5v when switched on/off.

I can read individual PPM signals from any other pin, one at a time, but not on 7 or 8. They are useless.

I am firstly asking if getting a new (maybe upgraded) ATmega328 chip to replace the original 168 chip that I believe to be partially fried, will fix these 2 pins, or are there other components that might have been damaged on the arduino?

Secondly, does anyone know if there are any more interrupt handler pins on the ATmega328 than on the 168?

Thanks in advance,
jd
johndavid400
 
Posts: 7
Joined: Wed Feb 25, 2009 1:16 pm

Re: Possibly fried 2 pins on Arduino? help!

by adafruit on Mon May 11, 2009 3:18 pm

all pins can do interrupts, but they're the pin change interrupts not the 'hardware' interrupts. still, it would do pretty much what you want.
second, if you cant even blink an led, you fried the pin. just change the Atmega and you'll almost certainly be back on your feet

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

Re: Possibly fried 2 pins on Arduino? help!

by johndavid400 on Mon May 11, 2009 4:02 pm

thanks ladyada, is this the correct replacement?
http://www.adafruit.com/index.php?main_ ... cts_id=123

Also, since my pins 7 and 8 are fried I can't use my motorshield! I originally thought it was dead, and was about to replace it until I tested the Arduino... ThIs there any chance I can get some help re-assigning pins 7 and 8 in the AFmotor library to use the unused pins 2 and 12? I tried looking at the .cpp and .h files to re-define those pins, but I did not recognize the method used to assign some of the pins... namely 7 and 8.

Thanks again for your help,
jd

ps, I re-read the material and it appears that pin 8 is the only input capture pin...not interrupt handler, I got confused.
johndavid400
 
Posts: 7
Joined: Wed Feb 25, 2009 1:16 pm

Re: Possibly fried 2 pins on Arduino? help!

by adafruit on Mon May 11, 2009 4:30 pm

yes, you should replace the chip. there may be other problems with it, i dont suggest modifying the library & cant provide any assistance, although you are free to do so

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

Re: Possibly fried 2 pins on Arduino? help!

by johndavid400 on Mon May 11, 2009 7:05 pm

just ordered a new chip,
but, I needed to modify the library anyways if possible, since I will need to use pin 8 to capture the RC signal and then still be able to use the AFmotor library to run the motorshield, hopefully on a different pin than 8. Trying to integrate a typical RC system to control a robot by processing the signal through the arduino and driving the motors with the motorshield...
johndavid400
 
Posts: 7
Joined: Wed Feb 25, 2009 1:16 pm

Re: Possibly fried 2 pins on Arduino? help!

by adafruit on Mon May 11, 2009 7:38 pm

use a pin change interrupt on one of the analog in pins?

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm
Location: nyc

Re: Possibly fried 2 pins on Arduino? help!

by johndavid400 on Tue May 12, 2009 11:09 am

according to this thread about reading multiple RC signals with the Arduino, pin 8 is the only input capture pin on the Arduino (with the atmega168) that will allow for a serial input capture of multiple signals at the same time, to store and decode as needed... I wish there were another pin that offered this capability. I can capture the individual RC signals on any pin using pulseIn, but the processing power of the arduino limits that method to about 2 RC channels before it becomes overloaded and cannot run the sketch quickly enough to work.

I'll just focus on getting my Arduino back to normal for now... :?
johndavid400
 
Posts: 7
Joined: Wed Feb 25, 2009 1:16 pm

Please be positive and constructive with your questions and comments.