what do PIC and AVR mean

[samcheetah]

the subject says it all!!!!!!!!!!!!!!!

 

[Dan East]

I think PIC is generally considered to mean Programmable Interface Controller, although I've also seen Programmable Interrupt Controller.

After some googling it appears AVR isn't an acronym, just a made up name:
**broken link removed**
**broken link removed**

Dan East

 

[StupidDum]

They are different brand of microcontroller.
The major difference is, PIC instruction cycle is 4 machine cycles, while AVR need only 1 machine cycle. AVR is faster!

 

[samcheetah]

think PIC is generally considered to mean Programmable Interface Controller, although I've also seen Programmable Interrupt Controller

thats what i was confused about. can someone confirm this

 

[Nigel Goodwin]

think PIC is generally considered to mean Programmable Interface Controller, although I've also seen Programmable Interrupt Controller

thats what i was confused about. can someone confirm this

It's pretty well an Urban Legend, it's been debated lots and lots over the years - there seems no definitive answer, but 'Programmable Interface Controller' seems a common choice.

Don't forget, MicroChip were NOT the original manufacturers of the chip, they simply bought the rights to it - it was already called a PIC long before MicroChip appeared on the scene.

 

[Parag0n]

I always thought it was Programmable Integrated Circuit :\

 

[StupidDum]

that doesn't really matter.
as PIC is more well-known as .. a microcontroller..

 

[bmcculla]

I think the PIC was originaly intended to be a Programmable Interface Controller for a microprocessor. The microprocessor the PIC was connected to wasn't a success but since RISC computing was a hot topic of the day someone got the bright idea of selling the PIC as a stand alone RISC processor (instruction sets don't get much more "reduced" than the PIC). But StupidDum is right - none of this really matters because now the PIC is definately a stand alone microcontroller.

A programmable interrupt controller is something else.

Brent

 

[John Sorensen]

No one seems to be able to figure out what AVR stands for, either. Some people have speculated that it is the initials of the designers; others have made up different phrases to fit the acronym. If it stands for anything, so far Atmel ain't sayin'.

j.

 

[Nigel Goodwin]

No one seems to be able to figure out what AVR stands for, either. Some people have speculated that it is the initials of the designers; others have made up different phrases to fit the acronym. If it stands for anything, so far Atmel ain't sayin'.

I suspect they simply chose a three letter acronym (TLA) to try and compete with PIC :lol:

 

[John Sorensen]

I think they probably just liked the way it looked.

j.

 

[Noggin]

No one seems to be able to figure out what AVR stands for, either. Some people have speculated that it is the initials of the designers; others have made up different phrases to fit the acronym. If it stands for anything, so far Atmel ain't sayin'.

I suspect they simply chose a three letter acronym (TLA) to try and compete with PIC :lol:

Tha AVR PWNS TEH PIC!!!!11one

AVR up to 16 MHz operation (new ones will go higher)
Most instructions are 1 cycle, so very close to 1 MIPS/MHz
32 general registers
Register to Register architecture

Whats a PIC get up to? 20 MHz?
Maximum of 5 MIPS
Accumulator architecture

For writing assembly, the accumulator architecture is enough to make me balk at trying to write for a PIC.

PLEASE if I'm wrong on anything correct me.

 

[RonH]

Some pics go up to 40Mhz (with internal PLL) 10MIPS

the 14x PICS use acumulator but the 16X PICs can go register to register.

Not sure about the 16X PICS but the one 14XPIC I use (16F877) has 368 GP data registers.

Ron

 

[StupidDum]

Some pics go up to 40Mhz (with internal PLL) 10MIPS

the 14x PICS use acumulator but the 16X PICs can go register to register.

Not sure about the 16X PICS but the one 14XPIC I use (16F877) has 368 GP data registers.

Ron

A 40Mhz PIC's speed matches with a 10 Mhz AVR.
However, its efficient is less, in another word, consume more power.

 

[Nigel Goodwin]

PLEASE if I'm wrong on anything correct me.

Funny how PIC's are far more popular 8)

The AVR was an obvious move to try and get some of MicroChips business, the AVR was a simple copy of the PIC idea - with enough changes to prevent any copyright problems.

As to which is 'best', it's highly debatable, PIC's are far more popular, to the extent that PIC is often used as the name for any micro-controller.

 

[samcheetah]

hey lets be like good boys and girls (err are there any girls here :lol: ) and dont start a debate on whats good and whats bad. i just asked about the meanings of the acronyms PIC and AVR.

i have been attatched to the computer hardware industry for quite a long time and i see those people always fighting on such issues. such as Intel VS AMD and ATI VS nVidia etc. im glad to see such debates in electronics forums. it feels like home :lol:

anyway i learned alot from all that. u guys keep on if u want to.

 

[bmcculla]

The AVR isn't a simple copy of the PIC its a completely new archetecture designed to be a RISC processor. The PIC just happens to have a very small instruction set - its not a true RISC processor. Microcontrollers have been around for a lot longer than the PIC. Though I do agree that the AVR was an attempt to get some of Microchip's buisness.

As far as popularity being faster doesn't nessesarily mean that a controller will be more popular. Availability of design tools,existing code and expertise all play a part. The old 12 clock 8051 still makes up a huge number of the 8 bit micro's used in designs (way more than the PIC).

Just My two cents
Brent

 

[Noggin]

I think the PIC also has MUCH better classroom support which is one reason that its so much more popular. I think that Atmel is pushing for that classroom support with the STK500 kits though, at least in some places. Personally I'm leaned WAY towards AVR but thats mainly because thats what I have done most of my recent projects on.

 

[samcheetah]

i have a few questions

StupidDum said:

The major difference is, PIC instruction cycle is 4 machine cycles, while AVR need only 1 machine cycle. AVR is faster!

does that make the AVR faster. i mean does speed only depend on the instruction cycle. as i told u guys that i have been connected to the computer hardware industry for quite a long time. i have learnt from there that speed is not everything. its the architecture that has to be efficient. like AMD chips with lower clock frequencies compete with Intel chips working at higher clock frequencies. its because both of them have different architectures. so its not how fast a microprocessor works, its how efficiently it works!!!!! what are the advantages and disadvantages of the PIC and AVR architectures??

Noggin said:

AVR up to 16 MHz operation (new ones will go higher)
Most instructions are 1 cycle, so very close to 1 MIPS/MHz
32 general registers
Register to Register architecture

Whats a PIC get up to? 20 MHz?
Maximum of 5 MIPS
Accumulator architecture

whats the difference between a register to register architecture and an accumulator architecture. i have learnt that all microcontrollers use accumulator registers to store the results of operations e.g if we add A to B, the result C will be stored in an accumulator. so what is a register to register architecture.

For writing assembly, the accumulator architecture is enough to make me balk at trying to write for a PIC.

why is that so. actually im new to assembly. is it difficult to write programs for microcontrollers that use the accumulator architecture? what benefits does register to register architecture provide in writing programs using assembly.

RonH said:

Some pics go up to 40Mhz (with internal PLL) 10MIPS

i heard that usually the clock is generated with a crystal. what benefits do PLLs provide for generating clocks in microcontrollers. and is it common to use PLLs for higher frequencies?

the 14x PICS use acumulator but the 16X PICs can go register to register

is the 16F628 one of those PICs that use the register to register architecture??

and thanx for all your replies. i really appreciate that!!!

 

[Nigel Goodwin]

is the 16F628 one of those PICs that use the register to register architecture??

Because the PIC is a RISC processor you don't have many instructions, the 16 bit processors have considerably more than the 14 bit ones, which in turn have a few more than the 12 bit ones. Obviously with fewer instructions you pick the ones which matter the most.

The main difference though is that the PIC uses Harvard Architecture, whereas most (if not all?) others use Von Neumann Architecture. The basic difference is that Harvard keeps data and program totally seperate, where Von Neumann uses the same space for both.

Speed is rarely an issue, for most programs the processor will be sat doing nothing for most of the time - usually in delay loops, or waiting for an event.