Which Microcontroller to choose - Page 2 - Electronic Circuits Projects Diagrams Free

boxer4 · 2nd October 2007, 03:22 AM

Usually programming in C will produce code that's quite a bit less efficient than if programmed carefully in assembly. However, I've found that generally it's fair, and sometimes the simplicity of C overshadows the costs, in terms of time of writing and debug, of straight assembly. Of course, stuff that's *really* critical to get right, including dealing with running out of program memory, getting every single last byte through assembly is crucial.

Because C is much easier to write and maintain, I think I'm about to GPL my really simple AVR-C tachometer (configurable to both fake-analog or 7-segment) without actually building the circuit and getting other people to fix it... Actually, I'm planning on doing this to see how many people bite and build one despite that fact of missing the hardware sample.

I think both PIC and AVR assembly have their strengths and weaknesses, both have nice features, but I personally prefer AVR as it seems more natural to me.

Quote:

Originally Posted by nunotins14

Code:

#include "16F84A.h"
#fuses XT, NOWDT, NOPROTECT
#use delay(clock=4000000)

void main()
{
	if (input(PIN_A0) == 1)
		output_high(PIN_A1);

	else if (input(PIN_A0) == 0)
		output_low(PIN_A1);
}

I'm not sure what you mean by "stable" or about PIC C compilers, but typically, at least in avr-gcc, if you want to constantly monitor a signal to change another, you'll need to make an endless loop:

Code:

#include "16F84A.h"
#fuses XT, NOWDT, NOPROTECT
#use delay(clock=4000000)

void main()
{
        while(1)
	{
		if (input(PIN_A0) == 1)
			output_high(PIN_A1);

		else if (input(PIN_A0) == 0)
			output_low(PIN_A1);
        }
}

Now you should have a $6.00 line driver

**Nigel Goodwin** · 2nd October 2007, 10:13 AM

Quote:

Originally Posted by Sceadwian

How specifically is PIC assembler more efficient? Also what about complexity? Basic code in ASM specifically is a lot easier to understand on an AVR than it is a PIC

Presumably you mean that YOU find AVR assembler code easier to understand?, just because you do doesn't mean the rest of the world does. The far smaller instruction set means that many people find it easier to learn.

Personally I find PIC assembler far simpler, and so do many others - I think it really depends on your programming background?. I've always considered that a 6502 background means you find PIC easier, and a Z80 background means you find AVR easier.

Quote:

they both might be RISC based but the similarities stop there. A speed difference of 4 to 1 per clock is pretty big by anyones standards, which specific higher end PICS are you referring to vs which specific AVR's?

AVR's have a 4 times higher clock speed, but they don't run programmes four times faster - PIC assembler is pretty efficient, because it's very accurately targeted at doing a specific job. If you're trying to do micro-processor type applications?, then the AVR has significant advantages, as it's less specifically a micro-controller.

As always though , both will do almost all jobs, as will many other micro-controllers, it's really just down to personal choice.

nunotins14 · 2nd October 2007, 07:58 PM

boxer4 sorry i forgot that part...i did it too, if you notice i said the lad flashes, its impossible for it to flash without the loop

Guys what about the Intel 8051 family i read it controls over 40% of the microcontrollers market
Is it a good choice?

**Nigel Goodwin** · 2nd October 2007, 09:17 PM

Quote:

Originally Posted by nunotins14

Guys what about the Intel 8051 family i read it controls over 40% of the microcontrollers market
Is it a good choice?

It's a good choice if you have a job lined up programming for it - but essentially it's a very old, fairly low spec, design, a micro-processor that was modified to make it somewhat micro-controller like.

The reason it's around in large numbers is because it's made by lots of different manufacturers, and it's been about for such a long time.

If you search these forums you will notice that almost all posts regarding it come from India and the surrounding area - the rest of the world moved on from them a long time ago.

nunotins14 · 2nd October 2007, 09:51 PM

hmm...i just said this cuz im using them at school

Nigel what you use, what's the "best" for you, that has PWM, ADC etc?

**Nigel Goodwin** · 2nd October 2007, 10:50 PM

Quote:

Originally Posted by nunotins14

hmm...i just said this cuz im using them at school

Nigel what you use, what's the "best" for you, that has PWM, ADC etc?

I use PIC's which are by far the most popular amongst hobbyists, but if you are learning 8051 it would make good sense to go with that. Generally you can do what you want with almost any micro-controller.

Once you've learnt 8051 at school, and you want to move to something more modern, I would suggest the Atmel AVR - which is probably second in popularity, but more similar to the 8051 than the PIC.

nunotins14 · 2nd October 2007, 11:14 PM

hmm i see...but i cant find a cheap easy programming popular with PWM and ADC PIC :/, by the way...where is the radio project in your website?

Sceadwian · 3rd October 2007, 12:26 AM

With PWM and ADC? Lots of pics have both of those features, lots of AVR's have those features as well. There are cheap programmers by the dozen on the net and you can home brew SPI programmers with a few discrete components plugged into a parallel port and using software such as ponyprog. You can usually home brew something for a few dollars. Try actually looking =)

http://www.lancos.com/prog.html

Supports the bulk of the PIC and AVR lines as well as eeproms and allows communication to any device that use an I2c bus. Circuit schematics provided for all interfaces.

nunotins14 · 3rd October 2007, 01:34 AM

lol i know that there are many microcontrollers with these features, but my question was, cheaper with PWM, ADC, home made programmer, easy interface etc, you guys just say, there are many, you can use this you can use that, this site this this site that, but i want a reference

im using PIC16F84A, so, I should upgrade to ...? :P

boxer4 · 3rd October 2007, 03:11 AM

I was using a 16C84 and 16F84 on one of my projects but quickly switched to the 16F628A as it's much cheaper and easily portable (minus a few setup, my code directly ran on the 628A). The programmer was fairly simple. I also use the AVR 90S2313 and think they're about the same in terms of dev starter costs.

As usual I'd say don't use manufacturer to choose your design, use your design to choose your manufacturer. I still prefer AVR for its general purpose instruction set rather than a fairly hackish PIC architecture, though it's absolutely unnecessary to have general purpose. I like the general purpose nature because things like gcc can have natural backend mappers that work like any other CPU.

You know things are a hack when things like PCLATH and bank switches need to be monitored carefully... And the fixed stack size (though you wouldn't want to go too deep anyway) can be quite annoying. One thing I should have done on PIC is macro btfss as naturally I'd think the next instruction _should_ be executed if true, not skipped

nunotins14 · 3rd October 2007, 07:46 AM

Ok, we have many opinions, damn, why they make so many PIC's lol...but looks like I have some good info for the upgrade...

Thanks alot guys

**Nigel Goodwin** · 3rd October 2007, 09:12 AM

Quote:

Originally Posted by nunotins14

lol i know that there are many microcontrollers with these features, but my question was, cheaper with PWM, ADC, home made programmer, easy interface etc, you guys just say, there are many, you can use this you can use that, this site this this site that, but i want a reference

im using PIC16F84A, so, I should upgrade to ...? :P

As you're using the long obselete 16F84, the obvious move is to it's replacement the 16F628 - but for similar chips with ADC etc. look at the 16F88 and 16F819.

eblc1388 · 3rd October 2007, 10:15 AM

Trust us, starts with PIC because it is simpler to get something working with PIC first.

Then moves on to AVR, and this is what one gets.

For about the same price per chip, 32 general purpose registers(six of them can be used as three 16-bit address pointer), linear SRAM memory addressing without banks to worry about, unlimited stack level within reasons, vectored interrupt handling and free full-featured GCC C compiler.

I try not to mention the up to four time speed increases at the same crystal frequency as someone will jump in and said there is no point because most of the time the MCU is spent waiting.

The down side of AVR, unlike PIC, which is foolproof on this aspect, is in its fuses programming. Unaware learner can program an AVR into a state where he cannot access it again using more general programmer hardware. That said, the fuse information is clear and it is always the user fault not understand them or following them closely or not knowing what he would end up with a particular fuse setting.

Added: If one still wants to go ahead with AVR, the best one to try is the Tiny2313(20-pin). With 2K of flash, 128 Byte SRAM and 128 Byte EEPROM. One also gets a full 8-bit port and separate pins for serial RX/TX. Not even the bigger 28-pin brother Mega88 can beat that.

nunotins14 · 3rd October 2007, 09:25 PM

eblc1388 what PIC you recomend that fits my needs?

simrantogether · 4th October 2007, 08:11 AM

Well,

Atmel also has many varieties..

Atmel avr or 89 series

and microchip has pic and its many varieties..

Actually both are good...

1. AVR by Atmel is a fresh controller.. and you can get its easy to make programmer also very easily.. at ..

this page

and refer the websites for tutorials and projects:

www.avrfreaks.net
www.avrbeginners.net

---------------------------------------------------------------------

2. while pic has many advantages that.. you'll get a lot of material on internet to work with..

programmers are easy to be found in the market.. and easy to make at home also..

and a lot of people working with this controllers..

in other words.. lucky to start with pic..

Refer our moderators site for further clarifications:

www.winpicprog.co.uk

----------------------------

Please check my answer before taking decision..

Regards,

Simran..

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2nd October 2007, 07:58 PM	(permalink)
nunotins14	boxer4 sorry i forgot that part...i did it too, if you notice i said the lad flashes, its impossible for it to flash without the loop Guys what about the Intel 8051 family i read it controls over 40% of the microcontrollers market Is it a good choice?

2nd October 2007, 09:51 PM	(permalink)
nunotins14	hmm...i just said this cuz im using them at school Nigel what you use, what's the "best" for you, that has PWM, ADC etc?

2nd October 2007, 11:14 PM	(permalink)
nunotins14	hmm i see...but i cant find a cheap easy programming popular with PWM and ADC PIC :/, by the way...where is the radio project in your website?

3rd October 2007, 12:26 AM	(permalink)
Sceadwian	With PWM and ADC? Lots of pics have both of those features, lots of AVR's have those features as well. There are cheap programmers by the dozen on the net and you can home brew SPI programmers with a few discrete components plugged into a parallel port and using software such as ponyprog. You can usually home brew something for a few dollars. Try actually looking =) http://www.lancos.com/prog.html Supports the bulk of the PIC and AVR lines as well as eeproms and allows communication to any device that use an I2c bus. Circuit schematics provided for all interfaces. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

3rd October 2007, 01:34 AM	(permalink)
nunotins14	lol i know that there are many microcontrollers with these features, but my question was, cheaper with PWM, ADC, home made programmer, easy interface etc, you guys just say, there are many, you can use this you can use that, this site this this site that, but i want a reference im using PIC16F84A, so, I should upgrade to ...? :P

3rd October 2007, 03:11 AM	(permalink)
boxer4	I was using a 16C84 and 16F84 on one of my projects but quickly switched to the 16F628A as it's much cheaper and easily portable (minus a few setup, my code directly ran on the 628A). The programmer was fairly simple. I also use the AVR 90S2313 and think they're about the same in terms of dev starter costs. As usual I'd say don't use manufacturer to choose your design, use your design to choose your manufacturer. I still prefer AVR for its general purpose instruction set rather than a fairly hackish PIC architecture, though it's absolutely unnecessary to have general purpose. I like the general purpose nature because things like gcc can have natural backend mappers that work like any other CPU. You know things are a hack when things like PCLATH and bank switches need to be monitored carefully... And the fixed stack size (though you wouldn't want to go too deep anyway) can be quite annoying. One thing I should have done on PIC is macro btfss as naturally I'd think the next instruction _should_ be executed if true, not skipped

3rd October 2007, 07:46 AM	(permalink)
nunotins14	Ok, we have many opinions, damn, why they make so many PIC's lol...but looks like I have some good info for the upgrade... Thanks alot guys

3rd October 2007, 10:15 AM	(permalink)
eblc1388	Trust us, starts with PIC because it is simpler to get something working with PIC first. Then moves on to AVR, and this is what one gets. For about the same price per chip, 32 general purpose registers(six of them can be used as three 16-bit address pointer), linear SRAM memory addressing without banks to worry about, unlimited stack level within reasons, vectored interrupt handling and free full-featured GCC C compiler. I try not to mention the up to four time speed increases at the same crystal frequency as someone will jump in and said there is no point because most of the time the MCU is spent waiting. The down side of AVR, unlike PIC, which is foolproof on this aspect, is in its fuses programming. Unaware learner can program an AVR into a state where he cannot access it again using more general programmer hardware. That said, the fuse information is clear and it is always the user fault not understand them or following them closely or not knowing what he would end up with a particular fuse setting. Added: If one still wants to go ahead with AVR, the best one to try is the Tiny2313(20-pin). With 2K of flash, 128 Byte SRAM and 128 Byte EEPROM. One also gets a full 8-bit port and separate pins for serial RX/TX. Not even the bigger 28-pin brother Mega88 can beat that. __________________ L.Chung Last edited by eblc1388; 3rd October 2007 at 10:27 AM.

3rd October 2007, 09:25 PM	(permalink)
nunotins14	eblc1388 what PIC you recomend that fits my needs?

4th October 2007, 08:11 AM	(permalink)
simrantogether	Well, Atmel also has many varieties.. Atmel avr or 89 series and microchip has pic and its many varieties.. Actually both are good... 1. AVR by Atmel is a fresh controller.. and you can get its easy to make programmer also very easily.. at .. this page and refer the websites for tutorials and projects: www.avrfreaks.net www.avrbeginners.net --------------------------------------------------------------------- 2. while pic has many advantages that.. you'll get a lot of material on internet to work with.. programmers are easy to be found in the market.. and easy to make at home also.. and a lot of people working with this controllers.. in other words.. lucky to start with pic.. Refer our moderators site for further clarifications: www.winpicprog.co.uk ---------------------------- Please check my answer before taking decision.. Regards, Simran.. __________________ Simran.. 8051 Specialist.. Last edited by simrantogether; 4th October 2007 at 08:22 AM.