مقایسه PIC با AVR

[arahafrooz]

پاسخ : مقایسه PIC با AVR

تولید میکروکنترولرهای PIC از چند دهه پیش آغاز شده بنابراین application note های به مراتب بیشتری نسبت به میکروکنترلرهای AVR برای اونها وجود داره، از نظر حذف نویز هم وضعیت بهتری دارند و برای همین صنعتی تر حساب می شند. علاوه بر این نرم افزارهایی مثل FuzzyTech هم وجود دارند که از میکروکنترولرهای PIC حمایت می کنند ولی هنوز AVR رو ساپورت نمی کنند.....

[nsm]

پاسخ : مقایسه PIC با AVR

سلام
نرم افزار FuzzyTech چی ؟

[arahafrooz]

پاسخ : مقایسه PIC با AVR

[right]سلام
fuzzytech یه نرم افزار قویه برای پیاده سازی و شبیه سازی منطق فازی. همونطور که میدونید منطق فازی کاربردهای مختلفی داره که یکی از مهمترین کاربردهاش طراحی کنترلر فازیه. Fuzzytech این امکان رو فراهم کرده تا شما یک کنترلر فازی رو برای یک میکروکنترلر طراحی و شبیه سازی کنید و بعدا فایل hex مربوط به میکروکنترولر رو بهتون تحویل می ده. این نرم افزار از چند خانواده میکروکنترولر مثل PIC و HC12 و... حمایت می کنه. البته توی ایران هنوز طراحی کنترلر فازی جا نیوفتاده ولی مزایای زیادی داره تا اونجایی که می دونم اگه بخواهید که یه کنترلر برای پیاده سازی روی میکروکنترلر طراحی کنید یکی از سریعترین روشهاش به کمک این نرم افزاره. پیاده سازی کنترلر فازی بر روی میکروکنترلر اونقدر مهمه که در حال حاضر حتی میکروکنترلرهای فازی هم به بازار اومدند که میشه با دستورات اسمبلیه پایشون توابع عضویت فازی تعریف کرد....
برای اطلاعات بیشتر در مورد نرم افزار می تونید به وب سایت نرم افزار مراجعه کنید:
http://www.fuzzytech.com/

[vahid-elect]

پاسخ : مقایسه PIC با AVR

در مورد مثال های تفریحی ، لطفا :applause:

[electeron_man]

پاسخ : مقایسه PIC با AVR

سلام به همه ی دوستان.من قبلا بمدت 2سال با میکرو هایPIC کار می کردم و خیلی ازشون رازی بودم تا اینکه به یه پروژه ی تولیدی رسیدیم و می خواستیم که اونو تولید انبوه کنیم ولی متاسفانه مجبور شدیم که اونو با AVR طراحی کنیم که هنوز ادامه داره فقط به دلیل تفاوت فاحش قیمت.چون می دونید که در کاره تولید انبوه حتی یک ریال هم خیلی مهمه چه برسه به چند 100تومن.
من یه سری مطلب در مورد تفاوتPIC & AVR دارم که وقته ترجمشو نداشتم ولی امیدوارم که کارتون رو راه بندازه.اطلاعاته خیلی مفیدین شاید بعضی هاش تکراری باشه ولی منسجم و یکپارچس.


- PIC are really well known for their large "Hobbyist" following. But when I see carefully most of these use only lower end PICs such as 16F84 & 16F87x series and to some extent 18F series. I've rarely seen some serious discussion about high-end PICs.

- Due to this large PIC user base, some basic facts are very well established and available widely over internet.

- Someone in this post said that there are many questions about locked chips, erased flash etc. on AVRFreaks & other sites for AVR. This is true. But then these clearly shows lack of reading DataSheets throughly and understanding clearly before actually doing somthing in chip.

- Also same can be said about PICs. e.g. 12f675 chip. I had to read the datasheet twice before I came to know that, reprogramming 675 is not what it seems.(I also lost couple of chips before actually coming to a solution). Such issues also discussed in PIC forums but are less known.

- As far as reliability is concerned, I can't say much diffenence. I have designed systems with both PICs & AVRs. Both work fine under harsh conditions. (Within specs of chip of course).

- Breaking code-locks in MCUs. Well I don't have anything to say about it. This is possible for every data in every protected system.

- As I compare PICs & AVRs on their design basis I can say...

PIC
Advanteges:-
* Easy access to all RAM upto certain extent, but larger memories(?? anything greater than 128 bytes) require explicit bank switching.
* Easy programming & fuse setting(atleast for most PIC).
* Large fan(!) following, so you can generally get your doubts solved quickly by users all round the world.
* Tools which ease writing software, especially code that initializes on-chip peripherals.
* Very few instructions.
* Excellent simulator MPLAB to reliably test your HLL or ASM code.

Disadvantges:
* Single accumulator. & Accumulator centric instructions. Defeating RISC aim of large CPU registers for simplifying Instruction Set.
* A very bad Single/Two vectored interrupt system. If you have to manage the many real-time activities which are controlled by interrupts, it is really hard or shall I say nightmare.
* More the no. of interrupts, more time wasted in polling code.
* Lack of stack & stack manipulation(atleast for low & mid-range PICs) only add more difficulties. e.g. Just see how 32x32 multiplication is done on PIC for any compiler. All of them assign some 10-15 bytes of RAM for their internal use throughout entire program executution.
* On-chip peripherals are some-what less powerful when I compare them with AVR.
* Only one data-pointer. Not HLL friendly arch.
* Very retstrictive instruction set.

AVR:
Advantages:
* 32 general registers. You can use any of them as accumulator. 3 16-bit RAM, ROM pointers.
* Each interrupt has it own vector, no polling needed.
* Stack & Stack manipulate instructions.
* Large instrction set, easing many operations which require many instrunctions on PIC.
e.g. Try comparing two 32-bit nos. on PIC & AVR. or Multiply !
* Very efficient on-chip peripherals. 10-bit ADC, Differential ADC, PWMs just to name a few.
* Horse Power 20 MIPS @ 20MHz compared to 4 MIPS @ 20MHz for PIC without internal PLL.
* A free full fleged compiler GCC. HLL friendly arch.

Disadvantage:
* Releatively new in market.
* Small user base (Though this is changing fast as far as I know).
* Though there are Automatic Code Generators such as CodeVision etc. most users prefer writing
their own device-drivers.
* You will have to experiment & experience before you can be confident about AVR.(Well, This may be true for everything we learn new, but most just skip the datasheet reading and jump to coding & burning(!) chip.) You will get less ready-made solutions.
* Though AVRStudio is improving fast it still doesnot simulate many of the peripherals. You will have to program chip to see what actually happens.


Last & most important is COST. Well here AVR is clear winner. From developement tools to chips AVR offers much more at much less price. Just check the AVR Butterfly specs. For $20, you will be amazed to see how much you can get. Free C-Compiler !! Just 4 resistors for in-circuit programmer !!! What you need more ??

[size=12pt]کلام آخر که خیلی جالب وکاربردیه و پاسخ به تمام تردید های یه مهندس در طراحیاشه
See What is needded.. then what you know... then what is available.... then what is possible