Top new questions this week:

How to choose an ARM Cortex M3 microcontroller?

Based on my rough requirements of being in the 36 to 72 MHz range, having 16kb+ SRAM, 128kb+ flash, being programmable in C, I have decided that for my application I want to use an ARM Cortex M3 MCU. …

microcontroller arm

asked by YoungMoney 16 votes answered by Scott Seidman 14 votes

Why do refrigeration compressors stall when switched off and on quickly?

All of the air conditioners I've worked with have the following words on them: Before restarting, wait three minutes. In the event the air conditioner's compressor is switched off and back on …

motor induction-motor

asked by DragonLord 13 votes answered by horta 18 votes

What's the usage of these holes?

I'm really curious to know what are these holes on this mobile PCB: Are these vias? I doubt they are vias. If these are not vias then what are they? What's the usage of these holes?

pcb identification

asked by Roh 10 votes answered by Matt Young 17 votes

AVR flash memory corruption

This question is related to AVR deprogramming itself. Project info: We have a battery powered product using an ATMEGA644P. The application permanently runs in sleep mode and only wakes up once a …

microcontroller avr atmega flash failure

asked by Rev1.0 6 votes answered by Jacen 5 votes

4 layer PCBs with Fritzing

Can you use Fritzing to create a 4 layer pcb? Also, in real life, what is the maximum limit of layers we can use to create pcbs? is it 4 layers?

pcb pcb-design pcb-layers

asked by user1584421 6 votes answered by PeterJ 7 votes

Are more expensive parts worth it?

The prices of components of supposedly the same type and with the same parameters vary strongly between manufacturers. Assuming my use does not come close to the absolute maximum ratings, is it worth …

components buying

asked by Duoran 6 votes answered by Madmanguruman 15 votes

DDR bus design review

In our last build we had issues with DDR stability in our prototype, simply because of lack of experience with this type of high speed memory connections. We managed to get it working with halving the …

pcb-design memory layout signal-integrity high-speed

asked by julumme 5 votes answered by Rolf Ostergaard 2 votes

Greatest hits from previous weeks:

Why is AVR used in Arduino?

Why is Arduino using AVR? I understand that they are the official processor but there isn't a reason the code couldn't be ported to an ARM or a Freescale architecture other than cost, right? As long …

arm avr freescale arduino

asked by Chris Gammell 18 votes answered by Adam Davis 18 votes

Why use capacitors?

Why do you need to store the voltage for some time in a capacitor? I've always assumed circuits to work when you power it on and stop when you power it off. Why can't the whole circuit be drawn …

capacitor

asked by user1424 23 votes answered by Kortuk 25 votes

Can you answer these?

Electret Microphone cannot recognize human voice

I'm trying to transfer sound from an electret microphone to my speaker. I'm copying a simple circuit from the Internet with 5V source from USB and a 1Kohm resistor. However, because I don't have a …

electret

asked by user46199 1 vote

Fixing 1 failing timing constraint in Xilinx

In the end of my project I have a timing constraint failure as follows : clk_in is the 100 Mhz system clock on ML507 I don't know why it is not meeting the criteria, I don't know what the criteria …

vhdl xilinx timing optimization timing-analysis

asked by Anarkie 1 vote

How can I stop MPLAB X from hanging between build and program?

I've been using MPLAB X and XC16 to build and program projects for a dsPIC 33EP128MC506 for about a year now. For the last two months, I've seen some new and unusual behavior on two separate machines. …

pic mplab compiler

asked by Stephen Collings 1 vote