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The problem is caused by harmonics when motor spins. You can do following tests to prove it.
1.) Split microcontroller power, ground with motor power, gnd at power input ( assume motor has an on/off control circuit )
2.) Add big reservoir cap. as close to mcu power as possible
3.) Cover...
Hi Sribangaram,
The pins are multifunction function pins that are set by program. In other word, you can appoint these pins to one of the defined function. But, you cannot use same pin with different function simultaneously
GPIOs : they are general purpose I/O pins. These pins may be...
Hi Joshuacp,
I have doubt on the design because Tx and Rx are directly to each other.
Part A : a balun and change from differential to single end input or output
Part C : matching for rf input
Part B :
C203 : Resonant with RFOUTP, RFOUTN pins and bond wire to remove reactance so...
Hi,
You should send your product to lab. and asks for quote.
- - - Updated - - -
The lab will tell you what tests your product need to do. e.g when apply CE certificate for Dect cordless telephone in Europe, you will need to fulfill following requirement.
1.) Safety
2.) EMC ( rf...
Hi ctzof,
Pcb layout, gnd loop have significant effect on esd performance. Generally, the shunt diodes should place close to USB connector so that the pulses will divert to gnd without getting into the system.
Hi,
For your interest, if this board will go through mass production :
It is a good practice to put a small dot ( e.g. 1mm dia. ) near a multi pin component ( e.g. cpu ). The purpose is to let ' Pick and Paste ' machine set origin ( use laser beam ) so that all SMD components will...
Hi ArticCynda,
3 big holes : 2 purposes
i.) Act as guiding when pass through SMD machine and during pcb level testing.
ii.) Fix to cabinet during casing
6 vias surround big hole :
To avoid copper plate torn off from substrate
Roger
dtmf generator circuit
One transistor is MPSA92, the other one is MPSA42 and both of them MUST use high voltage type transistors. Otherwise the NPN transistor will switches on when ring signal applies to it, as a result the isolation fails.
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