Register to reply

Shorting of digital high and ground

by satya77
Tags: digital, ground, shorting
Share this thread:
satya77
#1
Feb9-12, 09:21 PM
P: 39
Hi,

I generally work on embedded boards so i always had this doubt generally in any embedded board with micro controller the pins on the micro controller are located very very close, so if i am trying to see the voltage or some waveform on any of the pins using oscilloscope or multimeter and if it gets shorted with the adjacent pin or to the ground then does it damage the micro controller. In general what are the pins that should never get shorted. Any suggestions on this will help me to face the hardware more confidently.

Thanks and regards,
Satya
Phys.Org News Partner Engineering news on Phys.org
DIY glove-based tutor indicates muscle-memory potential
Tricorder XPRIZE: 10 teams advance in global competition to develop consumer-focused diagnostic device
Study shows local seismic isolation and damping methods provide optimal protection for essential computing equipment
yungman
#2
Feb9-12, 09:32 PM
P: 3,898
The only way to have more confident is getting a good low power microscope or a good magnifying glass and very good lighting. Look at it, use a ohmmeter to measure between pins. And then it help you get extra parts to replace and a good solder station to remove and replace the chip!!!!

Seriously, you can only do so much and say a prayer!!! Do the best you can and cross your finger. You got to move on at some point of time. Double check, look carefully. That's all you can do. It die, you cry!!!!

I am not being bad, it's just life. If you never smoked up the room, you're not an engineer!!! I just did!!! I just smelled the dragged smell of a pan fried opamp last week!!! I was so careful to check all the pins and hooked up Vee to +V and Vcc to ground!!!!
cepheid
#3
Feb9-12, 11:21 PM
Emeritus
Sci Advisor
PF Gold
cepheid's Avatar
P: 5,196
Quote Quote by satya77 View Post
In general what are the pins that should never get shorted. Any suggestions on this will help me to face the hardware more confidently.
Also, I don't know that we can really give you a general statement about what pins should never be shorted. It depends upon the chip and circuit in question. Generally speaking, shorting power to ground is usually bad, but it's tough to say in general how much damage might ensue. Some chips have overcurrent protection. Yungman's advice to just be more careful, although it may sound trite, is probably the best thing we can say. Also, having the right tools can help a lot. If you can afford it, maybe you can look into getting some ultra thin probes that are designed for surface mount ICs etc.

A trick I once used was to temporarily solder a wire to each pin that you are trying to probe. Then you can clip the scope/multimeter probes to the free ends of those wires, which can be much farther apart from each other. However, this soldering itself may be tricky on surface-mount ICs with very closely-spaced pins. I can't remember now, but I think I may have managed it on one surface mount IC and a couple of through-hole DIP ones.


Register to reply

Related Discussions
High speed proving ground circuit General Engineering 0
Probing high speed digital circuits Electrical Engineering 3
High frequency from AC tig welder affects digital ammeter? Electrical Engineering 5
Shorting a switch elctrically Electrical Engineering 15
HOw can an egg fall from a high placeto the ground without breaking? Introductory Physics Homework 4