Is there is big diffrence between 16f628 and 16f628a

hef4011bp, how does it work

I made several LRC meters with PICs, but I was not able to measure inductance in low units < mH. There is many parasite features which make this measure difficult.

measure time in diffrent places at the same time

Keeping your leads short and good part layout will help.

floating point+pic16f628

The biggest difference between the 628 and 628A is the speed. 628A can run up to 20MHz. 628 can only run 4MHz. There are probably minor changes in the timing (due to increased speed), but almost anything that will run on a 628 will also run fine on a 628A.

skillnad 16f628 16f628a

i had similar problem long time ago it was in the configuration
notice : in the data sheet of both (628 & 628a) there is a diffrent in the configuration

pic 16f628 lc meter

i heared diffrence is in programming metthod..

16f628a

no not much

Added after 22 seconds:

nops

16f628a calibration

Fragrance said:

Hi

I was doing a project from epe called lcf meter I faced a strange problem when I used 16f628a the code does not work as it should but when the same code program in 16f628 it’s work fine with out any problem.
....
regards
Fragrance

Click to expand...

I have the same problem with the same project. The chips in question (16F628A) was programmed by Junebug/Firefly combo programmer (from Blueroomelectronics, BTW), so programming shouldn't be a problem (at least, it went well).
While LCF meter is booting, it shows "capacitor time out", and only after 3rd or 4th power on/off attempt it booting as it should be. But displayed frequency is bit higher ("310000hz") than an author's. Used exactly the same HEF4011BP chip as author's. Tweaks with 68pf cap didn't help.
From time to time then I'm measuring Caps over 0.1 mkf it can freeze and doesn't respond anymore.
I saw on EPE magazine forums site the author recommended someone with similar problem to use 16F628 chip, not 16F628A.
Any solutions/suggestions?
I'm relatively new to PICs (while I do have experience with other electronics).

compare 16f628 and 16f628a

Which version of the LC meter did you build? (what site)?

desamblador pic 16f628

Sometimes, "A" types imply:

changes in the hardware
changes in the programming algorithms

I consider them a different micro, just in case. I don't try to force the idea if similarity in my mind. It makes life easier.

16f628 16f628a differences

blueroomelectronics said:

Which version of the LC meter did you build? (what site)?

Click to expand...

The one from EPE magazine Feb 2004. Although it is possible to find that article on Internet - I cannot provide the link here to download it. It is reqiured to pay the subscription fee to download that magazine or article alone in PDF format, so posting any link here would be illegal, I guess.

Also, couple days ago I made another board with modifications from **broken link removed** . I used the same chips as before (pulled them out from sockets) plus extra 74HC132D according to link above(SOIC case).
All I'm getting right now is "Capacitor time out" which even worse than I had before, as it doesn't go anywhere from this point.

To compare which LC meter is better, I even made at the same time that LC meter you mentioned above. Updated schematics and software I got from site **broken link removed**
But I was having problems with this project, too! It was measuring caps and showing only about half of nominal value after calibrating (565-600pf instead of 1000pf with different caps of the same value). Frequency was about right, and ajustments by "+" jumper could not fix almost 100% discrepancy. Any attempts to measure caps over 0.1Mf resulted showing the same result ... about 1000pf... (???)
I used the same chip (bought at same place and time as another one mentioned above) 16F628A , same Firefly programmer, no positive result... so far...

According to author, this "updated meter" has the same limits as his previous project: **broken link removed**
Project from EPE supposed to be better (max caps range-wise)... But looks like something is not right about those 628A as both authors used 628, not 628a...

I'm not giving up fight, though... Asking for help, open for suggestions...

Just to let you guys know - I finally figured it out (thanks to guys who fixed code for PIC16F628A).



As it turned out, the code indeed has to be changed if you're going to use 628A controller instead of 628.
So this LCF meter is actually working OK with 628A controller.
However, after doing extensive search on Internet and after
numerous tries and PCB designs I also have found and made another (much better) version of LCF meter (wider ranges, added Programmable Signal Generator function etc).
If somebody interested, I can find the URL and post it here.[/b]

Found it:

Hex codes and schematics:
**broken link removed**

PCB layout (SprintLayout5 format):
**broken link removed**

Article is here: (in Russian, though, but I found English user manual on Internet as well).
**broken link removed**

Let me know, if somebody need help with it.

Free versions of the software to see schematics and PCB layout can be downloaded from http://www.abacom-online.de/uk/html/produkte.html

Here is full User manual for this device in English:
This product dosn't exist anymore on their website nor this manual (I saved it just in case). It will be useful is you decide to build this nice meter yourself.

Besides well-known LC meter (this version is with much improved resolution), this meter also has 2 Frequency meters: one up to 65MHz and another up to 3GHz.
Max F depends only on prescaler - can be used almost any found in your junkbox).
I used 1,3Ghz (SP4740) in mine.
Also it has 2nd C-Meter for capacitors ranging from 0,1mk up to 10000 Mkf, which is not so many even commercial meters have.
And finally, Programmable Signal Generator up to 1MHz.
Very useful meter for a test bench! And all if it was packed into tiny cheap 16F628A CPU!

Ruslan_Windrivers said:

Found it:

Hex codes and schematics:
**broken link removed**

Click to expand...

Thank's Ruslan_W, for all the links, and the English manual.
I wonder if the code (above link) contains English text or is it Cyrillic?
In the manual I saw both displayed..
The project looks very interesting.

@t said:

I wonder if the code (above link) contains English text or is it Cyrillic? In the manual I saw both displayed..
The project looks very interesting.

Click to expand...

Default language is changeable during initial setup of the meter (how - described in the manual - see page#6 for details)

Below is file containing 3 latest versions of the firmware for this project.
("2.6auto" is the latest one). Manual is describing "auto" firmware versions.

Ruslan_Windrivers said:

Default language is changeable during initial setup of the meter //
Below is file containing 3 latest versions of the firmware for this project.

Click to expand...

Thanks Ruslan_W, for the info, I hope to try it out soon. At.