Please reload the v3 program listing as I corrected an error... Sorry!!!

 

Hello again,
Still havent tried the new firmware- I've been spending all my spare time designing the PCB. Its hard work fitting all that stuff on a tiny board!
Just about ready to make it, though.

I've been buying in the components and I have a wee question,

A supplier has offered me a cheaper alternative to the 16F628A- he has some unwanted 16F627A that I can have for almost half the price.

I looked up the spec, and the 627A has only 1.5Kbytes where the 628A has 3.5Kbytes. For these short programs that would be okay- wouldnt it?
It was the only difference I could find.

What would be involved in making the programs run on the 627A? - it would save a fair bit of cash.

Thanks again

-Dal.

 

hi,
Looked at 627A spec sheet, its only got 1024bytes flash memory, IIRC the program isnt that big, everything looks the same as the 628A.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Nice one, I'll give it a go.

In terms of the ASM files- would I need to do anything other than change the chip name at the top?

Sorry- that probably sounds really pathetic... I do have pic training materials that I plan to study (lots)- just havent yet

-DAl.

 

As you suspected, just change the device under the "configure\select device" menu and change the include filename and device type at the top of the file.

Mike.

 

You probably don't even need to do that?, a 628 HEX file will load and run in a 627, as long as it only uses the first 1K of memory. The 627 has 1K (like a 16F84) and the 628 has 2K, otherwise they are identical.

But obviously it makes sense to change the name in the assembler file if you're re-assembling it.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Excellent- saved a few bucks and learned something! :-)


I've finished my PCB design- so off to the fabricators and then a wee wait- and I'll be laughing.

I'll post back when its done to let you all see it.

Thanks again.

-DAlmation.

 

Sorry for the late reply but it seems you've received all the correct answers from the gang.

Say, how 'bout showing us a BMP or JPG screenshot of your layout?

Mike

 

Both are REALLY bad suggestions, use either GIF or PNG, much smaller and perfect quality. BMP is perfect but absolutely massive (and isn't a supported format), JPG is poor quality and still far too large.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

no probs- I'll post a pic when the missus lets me back on the laptop. I'll warn in advance, though- its a very busy design!

I have a powerplane on both sides of the board and 1 on the middle layers (4 layer board). I'll remove them for clarity.

-Dal.

 

The 3D renders of the hex display isnt exactly wonderful- but you get the idea. Board designed with National Instruments "ultiboard".


Image1.jpg

Image2.jpg

Image3.jpg

Image4.jpg

Image5.jpg

 

It looks very nice Dal...

Mike

 

Mike,
I'm waiting on the PCB's arriving, but in the mean time (for future use) I was having some thoughts...

I currently have 4x 16F628, would it be technically possible to use 2x 16F59 (pinout attached). It has 33 i/o pins. I dont know how the port arrangement affects things.

the 16f59 is really cheap compared to the 628 and I migh be able to get it down to a 2 layer board with the lower component count (half as many IC's, resistors and transistors too).

I know it would be a total reprogram job (and I'm not looking for that), but is it possible?

16F59.PNG

Let me know your thoughts on the subject.

Thanks in advance.

-DAlmation.

 

Funny, I was thinking about different designs too (grin). Let me peek at the Data Sheet and get back to you.

Mike

 

Mike, K8LH....

You've put in a lot of work to make this project happen for me and I really appreciate it- Thanks go out to you and everyone else who has contributed.

I was hoping you could help me out with one final project problem...

-I have my PCB's and I have built some prototypes.
-I am using Version1 of your ASM (2 and 3 work, but I find 1 suits best).

-I have used 16F627 (not A) chips on the board as some became available to me very cheap. -I assemble your asm, then set my programmer for 627 and choose my config options there)

-The board works great, but it has a slight problem- I have a switch which calls up memory locations for this circuit to read. When switching, under some circumstances something in the PIC crashes the main board, leaving me with no readout (pic circuit carries on, but shows zeroes).

Anyways- I replaced the chips with 16F628A on one board and the problem has completely gone away- I dont fully understand the problem, but that definitely solved it.

When I use the 16F627, I cant enable code protect either and I am pretty sure the gremlins are something to do with me using 628A firmware on a 627 (slightly different commands and configs?)

I tried to edit your ASM for the 627 but I fell flat on my face each time.


Could I possibly impose and ask you to edit the V1 ASM to match the 16F627?
It is the last hurdle in a very long race, and it would be brilliant!!

Thanks again, mike.

-Dalmation.

EDIT- I have purchased all the 16f627's to complete the project- otherwise I would just use 628A's to solve the problem- sorry to be a pain. I'll take some photos of the PCB/circuit shortly.