Hero999

What do you mean chassis? I think you're probably takling about the box?

The great thing about this project is it didn't cost me much in terms of personal time and money. I only payed for the ZIF socket (pretty cheap off ebay, I can't remmeber how much) and the copper clad board and etching materials, everything else was borrowed from either work or college . I've not been busy at work for the last few weeks (we're in between projects and I have been booking to waiting) so I could assemble the whole thing at work, the only bit I did at home was etching the PCB!

The box was slavaged from an protoype the company had destined for the bin. It already had a few holes drilled in it but this was no problem as, for the most part, I needed to drill bigger hole in the same places, there was one hole where that wasn't the case so I just filled it with resin and as I've painted the whole thing with spray paint you can't see it anyway.

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Hero999

Right, I have installed WinPicProg and the program driver under WINE and it loads up with a couple of error messages.

"WARNING - Loaded file has changed do you wish to reload?"

How can the file have changed I haven't used it before?

"DLPORTIO.SYS device driver has not loaded.

Port I/O will have no effect."

Apart from that, the user interface appears and it appears to be fully functional.

I've still yet to get my hands on some PICs but I assume this error message means that it won't work under WINE as the driver hasn't loaded. This is no surprise to me, I wasn't expecting it to work but I just wanted to have some fun trying.

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Nigel Goodwin

Can't say I've ever tried it?, but I wouldn't expect it to work under WINE.

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Hero999

I've reasearched the most common suppliers in the UK:
RS PIC12F508-I/SN £0.62
RS PIC10F200-I/P £0.62
RS PIC12F509-I/P £0.69
RS PIC10F202-I/P £0.71
RS PIC10F204-I/P £0.71
Maplin PIC12F629-I/P £1.45 (Web Only)
Maplin PIC12C508A-04/P £1.51
CPC PIC12C508-04I/P £2.20!
All prices include VAT.

I've realised the the biggest cost will be shipping, Maplin charge £2.99 (free for orders >£35) and RS charge £7.50 (free for business account holders). Now as I don't have a business and I don't plan to spend more than £35 I think I'll probably end up picking it up from the store.

I'll probably end up going to RS and buy 10 PICs at £6.20 rather than being ripped off at Maplin even though it is further to travel. The question is as which PIC is generally better, the PIC12F508-I/SN or the PIC10F200-I/P? Are either of them going to go obsolete soon?

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Nigel Goodwin

PIC's don't really go obselete very fast, they even still make antique OTP devices!.

But most PIC's are pretty interchangeable, with only very minor changes required to the code, as there's only a fairly small number of PIC cores.

Are you looking for particularly tiny devices?, all those you list are 8 pin or less?. It really depends what you're wanting to do?, for learning purposes I would suggest the 16F628, or 16F88, or 16F819 - all easy to use 18 pin devices, all using the same 14 bit core - as do the 12F629 and the 12F675, which are 8 pin versions you could port to.

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Hero999

The bathroom fan project will only require a small PIC, I suppose I haven't thought about anything else at the moment.

I could just buy a few of the eight pin variety, I need a few just in case I destory some of them, then a few more of the 14 and 18 pin varieties.

I'm just no fan of drilling holes and would also rather pay less than more, I don't like the idea of using a PIC with 18 pins when an eight pin PIC would do.

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eng1

The PIC12C508A is an OTP device, not recommended.
The PIC12F508 looks good for your project, but it's not loaded with peripherals - that might become useful for future projects (ADCs, PWM) - and has a two levels stack. I would buy some PIC12F683s too (my personal favourite).

Gayan Soyza

You are going to make a Bathroom Extractor Fan Timer. After completing, the PIC must there permanent. So a FLASH based chip for that job would pointless. It can replace by an 8 pin OTP chip.

Due to very first time programming it must done with a FLASH based chip formatting over 100 of times to get the final output. After that can be converted to an OTP device. If you still don’t like then can replace the chip with a FLASH based one.

Looking at your requirement deeply

Pull the switch once – TURN ON output for 10 mins
Pull twice – TURN ON continuously
Pull again - TURN OFF

When it pulls ONCE within the 10 minutes time period what will happen? Does it continuous the timer or else?

When it pulls TWICE within the 10 minutes time period what it needs to do or do nothing?

For additional it will be good if you place 2 LED’s – one for 10 mins timer running & other for continuous running. Due to false input given by the user.

This small small things very useful when programming microcontrollers.

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Nigel Goodwin

That would make sense for production purposes, but for a 'one of', or just a small quantity, you may as well just stick to the FLASH chip, the difference in price is only small.

Even if you were moving to an OTP, you really need a UV eraseable one in order to do the changes required for the OTP, and to avoid wasting them.

But mostly pointless these days, use the FLASH chip!.

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eng1

When you program OTP devices you must be sure that your program works as you expect as you can't make any changes. Even expert programmers often need to modify/update their programs.
Don't waste your time and money with OTP microcotrollers.

pc88

Hi,

I was wondering if the PIC gurus here could bring me up to speed on how
development works in the PIC world. I have a lot of experience for AVRs but
none with PICs.

In particular, I was curious if PICs have in-circuit programming capability. For
instance, I've done all my AVR programming with the programmer described
here:

http://www.milkcrate.com.au/sensing/programmer.html

and I can program the uC while it is in the application circuit. Can the same
be done with PICs (or certain model PICs)? I have used uC's and programmers
that required you to remove the uC from the application board and re-insert it
after programming it, but it was too tedious and I fried too many chips. ICP
(in-circuit programming) is much, much more convenient.

Thanks!

Nigel Goodwin

The vast majority of PIC's allow ICSP, where do you think Atmel copied it from for the AVR?

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Hero999

Exactly and being a nube to PICs I'm likely to mess it up the first time round so ruining a load of OTP devices would prove more expensive than re-erasing and re-programming one device.

I can put up with UV erasable because I do have a germicidal tube lying around but a FLASH unit would be more convenient.

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3v0

There is no good reason to use OTP devices except in mass production where saving a few cents on each unit adds up to big dollars.

EPROM is just out and out outdated. There may be some corner case where it is a good solution but I do not know about it.

See Disclaimer Below.

Regarding the PIC development cycle.

Build->Program->Run

or

Build->Program->Debug (ICD vis ICSP)

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Nigel Goodwin

Have you seen the price of the JW PIC's though!.

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