16F84 vs 16F628

From the sound of things you just need to look at the datasheet?.

But I'll repeat again (as usual) the 16F84 was replaced by the 16F628 last century, and you shouldn't be looking at using it.

Nigel Goodwin said:

But I'll repeat again (as usual) the 16F84 was replaced by the 16F628 last century, and you shouldn't be looking at using it.

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And, I'll repeat again that I cannot find anywhere on Microchips website that states the 16F84A is obsolete! On the **broken link removed** it clearly lists it's status as "in production".

Mike.

Pommie said:

And, I'll repeat again that I cannot find anywhere on Microchips website that states the 16F84A is obsolete! On the **broken link removed** it clearly lists it's status as "in production".

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I didn't mention 'obselete'?, I mentioned that it had long been replaced by the 16F628 - which in my opinion renders it obselete anyway! - and it has long been listed as "not recommended for new projects".

From MicroChip's position they must be laughing all the way to the bank - selling an antique low spec chip for considerably more money than it's higher spec replacement!.

Nigel Goodwin said:

I didn't mention 'obselete'?, I mentioned that it had long been replaced by the 16F628

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Microchip have never suggested that the 628 is a replacement for the 84 as evidenced by the lack of migration documentation (see **broken link removed**). I remember it being listed as "not recommended for new projects" but that listing has now changed to "in production" and so I must conclude that it is now usable for new projects. The only thing wrong with the 84 is erm, nothing, except it's slightly dearer.

I also think it is not very helpful to keep pointing out to posters that they are using older parts as a lot of people do not have access to newer pics due to where they live and/or school requirement etc.

Mike.

Pommie said:

Microchip have never suggested that the 628 is a replacement for the 84 as evidenced by the lack of migration documentation (see **broken link removed**).

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There certainly WAS a migration document!, it's so old now it's probably been removed?.

I notice that list also doesn't have a migration document for the 16C84 to 16F84 either, does that mean the 16C84 wasn't replaced either?. And, like the 16F628 migration document, there certainly was one back when it occurred.

I have no problem with people using old stocks they have (I still use 16C84's I've got knocking about), but people are buying 16F84's to use in new projects - if people don't tell them it's not a good idea, how do they know?.

Nigel Goodwin said:

There certainly WAS a migration document!, it's so old now it's probably been removed?.

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Why would microchip remove documents?

I notice that list also doesn't have a migration document for the 16C84 to 16F84 either, does that mean the 16C84 wasn't replaced either?. And, like the 16F628 migration document, there certainly was one back when it occurred.

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But, it does have 16F83 to 16F84A and 16C622A to 16F628A, which would be from the same era. I remember seeing a document on Don McKenzie's site, is this the one you are thinking of?

I have no problem with people using old stocks they have (I still use 16C84's I've got knocking about), but people are buying 16F84's to use in new projects - if people don't tell them it's not a good idea, how do they know?.

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That is the point, they don't need to know because it hasn't been replaced and there is nothing wrong with the 84. Anyone in production will use the cheaper alternative but the price/complexity issue just isn't worth it for the beginner.

The advantages of using the 84 far outweigh the slightly higher price for a beginner.

Mike.
edit typo.

For newcomers is good to make them aware about. Why not.

You realize that after some time dealing with all thsi stuff.

Pommie said:

The advantages of using the 84 far outweigh the slightly higher price for a beginner.

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Why is that?.

Nigel Goodwin said:

Why is that?.

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1. There is such a vast amount of software readily available for the 84. I know that you only have to move the start of the variable area and write to CMCON to make it work on a 628 but that is far beyond most beginners and, if only the hex file is available, beyond a lot of experienced programmers.

2. There is a huge number of circuit that utilise the 84. You can tell beginners that it will work with the 628 with just a small mod to the source file. If they go ahead and build it, they will not know why it doesn't work because two things could now be wrong, the hardware or the mod to the code.

3. Most (probably all) of the simple programmers work with the 84.

4. Lots of school curriculum's are based on the 84.

5. The reason Microchip have not replaced the 84 is due to the above.

6. The 84 cost $2.71. The 628 is $1.29 - it just isn't worth the effort to save less than one pound.

7. There is absolutely nothing wrong with the 16F84A.

8. There only appears to be you that says it's been replaced with the 628.

Mike.

Pommie said:

6. The 84 cost $2.71. The 628 is $1.29 - it just isn't worth the effort to save less than one pound.

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More then 200% for an inferior device!, and that's not a concern?.

7. There is absolutely nothing wrong with the 16F84A.

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No, apart from it's age, and the fact it was replaced years ago, for that matter there's nothing wrong with the 16C84 either.

8. There only appears to be you that says it's been replaced with the 628.

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And the MicroChip migration document!, and the "not recommended for new projects" which even you admit to seeing!. I'll see if I can find the migration document, I certainly downloaded it from MicroChip - but it's almost a decade ago now, so it depends if I have any backups left from back then? - certainly the hard drive it was on is long gone!

Nigel Goodwin said:

No, apart from it's age, and the fact it was replaced years ago, for that matter there's nothing wrong with the 16C84 either.

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There not old, they still make brand spanking new ones and it's still not been replaced. The flash part was definitely a step in the right direction and Microchip don't supply the 16C anymore so they disagree with you there.

And the MicroChip migration document!, and the "not recommended for new projects" which even you admit to seeing!. I'll see if I can find the migration document, I certainly downloaded it from MicroChip - but it's almost a decade ago now, so it depends if I have any backups left from back then? - certainly the hard drive it was on is long gone!

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Yes, it was there, but microchip never said it had been replaced and they now appear to have reinstated it as a "in production" part. Maybe the "not for new projects" confused people into thinking it was either obsolete or had been replaced. As for the migration document, I'd be very interested to see it.

Whatever has gone before, Microchip now list the 84 as a production part and so it should not be refered to as obsolete or replaced.

I listed 8 reasons in order of most important first. You answered the last three.

Mike.

eng1 said:

Hi Mike. I agree with this statement And I think that beginners can enjoy building their first circuits even if they use an old uC.
But some novel features sound interesting: I think of the wide operative voltage range and the internal oscillator.

Regards

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You are quite right. The newer pic chips are far superior to the earlier ones. However, the 16F84A was a revolution when it was released and will work from 2.0V to 5.5V and is still probably the best chip for a beginner. I personally use the 16F88 for most 18 pin work as I find it the most flexible. I just think the constant "your living in the last century" is unhelpful.

Mike.

Pommie said:

There not old, they still make brand spanking new ones and it's still not been replaced. The flash part was definitely a step in the right direction and Microchip don't supply the 16C anymore so they disagree with you there.

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The 16F84 isn't a FLASH part, it's an EEPROM based part - the sole reason for it replacing the 16C84 was due to the relatively poor protection on the 16C84 - which was why they even kept the same number.

Yes, it was there, but microchip never said it had been replaced and they now appear to have reinstated it as a "in production" part. Maybe the "not for new projects" confused people into thinking it was either obsolete or had been replaced. As for the migration document, I'd be very interested to see it.

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No confusion, MicroChip actually stated it had been replaced by the 16F628, published a migration document, and listed the F84 as "not for new projects".

Due to the continuing demand, and the fact they can charge more than double for an inferior chip, possibly they have reinstated the F84?.

I'll keep looking for the migration document!.

I listed 8 reasons in order of most important first. You answered the last three.

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Sorry, but none of them sounded very convincing? - we're not still using horses and carts, by that argument we should still be doing so!.

Converting 84 code to run on a 628 shouldn't be beyond a beginner, and converting even HEX code certainly shouldn't be beyond anyone with a slight amount of experience, never mind an 'expert'.

We probably shouldn't be destroying '4electros' thread, so I'll see about moving the offending posts to a new thread.

Nigel Goodwin said:

The 16F84 isn't a FLASH part, it's an EEPROM based part

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Microchip list it as an "Enhanced Flash/EEPROM" part.

No confusion, MicroChip actually stated it had been replaced by the 16F628, published a migration document, and listed the F84 as "not for new projects".

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I still maintain that Microchip never even hinted that the 628 replaced the 84. A search of the web didn't turn up any links to a migration document.

Converting 84 code to run on a 628 shouldn't be beyond a beginner, and converting even HEX code certainly shouldn't be beyond anyone with a slight amount of experience, never mind an 'expert'.

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You have to be joking. Convert a hex file. Adding code to turn off the comparators may be simple. Moving the GPRs from 0x0c to 0x20 is next to impossible for most people.

Mike.

In Oz there is no price difference - the 84A and 628A are $9-95 each.
The 88 and 877 sell for $12-95.
All the major electronic retailers here continue to stock the 84A - I wonder how many they sell?

kenmac

Just my 2c worth.

For small 14bit PICs I like the 16F628A I have the ICE for it, or (personal favorite 16F88).
The 16F84 requires an external clock, this makes it more expensive than the already cheaper 16F628A.
Most people put a 4MHz resonator (approx 5% accurate) compared to the 1% two speed osc in the 16F628A. You also get nanowatt tech in the 16F628A and 16F88.
The 16F88 has debug mode, if you're learning it's makes even complex chips like the 16F88 far eaiser to understand.
The 16F88 has almost everything the 877A has, plus a 8 speed 1% clock.
The 16F88 can be used with a bootloader.

As for the 16F84 vs 16F628A This site sums it up.
http://finitesite.com/d3jsys/16F628.html

Even that site has updates...
**broken link removed**

beginners like F84 because there are many codes available written for F84 for them to learn (edit and experiment) and they will surely migrate after learning from it

Sure, there is quite a lot of example code for the 16F84, but there's also enough to get started on more recent PICs, like the 16F628 or 16F88...

your argument about it still being in production makes it seem like you don't realize the way companies like that operate. If their only market was hobbyists, it probably would be obsolete, but they have to deal with companies as well. the F84 was popular, and thus it probably ended up in a lot of commercial products, some of which are probably still in production or active use. Even for something as mundane as switching from one PIC to another, the cost of changing a product that is in production or active use can be very high, so it's easier for a company using them to simply keep doing so, and then phase them out the next time that they are doing technology upgrades for other reasons. I worked at a semiconductor manufacturer (where you would expect to see a lot of fancy technology) and they were still using some PAINFULLY obsolete software and hardware in important parts of their plant for just that type of reason (running OS/2 on 486 computers, or worse). Microchip then raises the prices sharply, so if companies really want to use them, it makes it worth their while to keep manufacturing them, and at the same time making them much less appealing for new designs... in addition to the other hints they drop, such as "not for new designs" and the strong public sentiment online that people should stop using it. Of all people, a hobbyist should be the most deterred from using it... there's no certainty that they will continue manufacturing it for long, it's way overpriced, and (compared to other, more modern PICs) it's really a piece of junk.

If you are really SO scared about getting started that you don't dare attempt it with anything but the "ford model T" of the PIC world, then get yourself one or two of them, take the example code you are so attached to, get a "hello world" program running, and then move it over to another PIC, such as the 16F628. Then you'll be starting with code you have tested and verified working, and only have to deal with the changes due to migration. And once you have successfully migrated to the newer PIC, take your 16F84's, throw them out the window, wave goodbye, and never look back.

As a professor of mine once said, "if you can flash an LED you can change the world". As most of us know, often by far the hardest part of getting started with PICs is successfully setting up the circuit and programming the PIC. Even having rock-solid example code won't help if you can't do that successfully, and getting that done is even easier on the newer PICs than on the F84, since you don't need an external oscillator on many of them. All you need is one "hello world" program that works on a newer PIC, and it can be just as good a starting point as a hundred 16F84 programs. read your books or websites, make changes to your 'hello world' code, and if things break you can backtrack to the last revision where things still worked. there's really not much reason you should need dozens upon dozens of example programs for anything but reference, in which case there's no real reason to actually use the F84 itself, instead of just taking ideas from the example code written for it

16F84 is a gost!! Come on...why someone whould buy a more expensive but with lower perfomance chip? U'l get a lot of circuits around 16F628 for starting and after a while u could migrate ALL proj for F84 on a 628. I never used a 16F84 and didn't kiled me. I've also learned migrating the code. I'm just a hobyst without a lot of free time.
Now I'm playing with a AT89C205.....if u realy like electronics don't be that lasy.
Btw...I think that most of the 84's are sold to hobyst and universityes.