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Why 2 Vdd pins for PIC microcontroller?

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abdalla

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pic vdd-pin

HI,

Why 2 Vdd pins for PIC microcontroller?

wht is better to connect one or both ?
 

pic24 avdd

I can only answer in a general sense, since you did not include a part number. The typical reason for multiple power pins on a small microcontroller is that one of the power pins feeds the analog section of the chip. By keeping analog power and digital power separate, noise in the analog section can be reduced. Digital noise on the power supply can cause inaccurate ADC readings for example.
Read the datasheet, the probably go into some detail as to what each VDD pin is for.
If you are not using the analog sections, usually it is safe to just hook the two pins together to a common power supply. It is usually not a good practise to leave the analog section un-powered when you are not using it.
 

microcontroller vdd avdd

Some parts have more than 1 Vdd or 1 GND, or have Vcc beside Vdd. Functions of the extra pins depending specific parts and not the same for every parts, even made by the same manufacturer and of the same family. Some parts are as exact as banjo said, but for some parts the extra pins are simply additional with the same function with the other pins just for ease of wiring.

You have no way to read the appropriate datasheets to understand well the specific parts.

nguyennam
 

why does the pic microcontroller has 2 vdd pins

dude connect those 2 Vdd to Vcc and 2 Vss to GND... simple as that dude... just follow what the datasheet told...
 

power supply pic both vdd pins

Pop a meter across the 2 vdd pins on most chips and you'll get a good old captain 0 Ohms, so in alot of cases they are cross connected inside the chip too
 

power on both vdd pins or just one

You should ALLWAYS connect ALL of the PIC power supply pins to apropriate power rails.
Once I did't connect AVDD(analog power supply-for the comparators, ADC etc.), since i figured I would't use any analog components in PIC.
After a lot of lost nerves and precious time trying to debug and find a cause, I found the basic rule of electronics:"If it's not powered it won't work(or not the way you want to)"
 

micrcontroller vdd avdd

foxabilo said:
Pop a meter across the 2 vdd pins on most chips and you'll get a good old captain 0 Ohms, so in alot of cases they are cross connected inside the chip too
Click to expand...
that`s right! but I think it has 2 VDD (PIC don`t have an AVDD like an AVR) just to supply enought current for the internal PIC pheriperals, some programmers, or just the ZIF on them, uses only one of the VDD pins...

some times I use only the upper pin (think its the 32 in a DIP40) And it worked very well... (just using PORTB) but a friend of a friend, connected just the bottom one, and It didn't worked!

so, connect both pins to VCC... or just one If you dare to...
 

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