Universal PI Micro

[bugwhiskers]

Hi Tinkerer and Sean,

I remember those days Sean, my first was the Sinclair ZX80 and I spent hours pouring over the Z80 opcodes, even memorised a lot of them.

Tinkerer, if you look through the SD2000 full schematics thread you will see a downloadable file that I posted there that performs all the timings. With minor modification the code can be changed to suit any ATMEL micro and is a good starting point requiring only minor changes to the code to suit your application.

One or the benefits of going down the ATMEL path is

http://www.avrfreaks.net/

Once you join the forum you can have any question answered by a host of experts. You'll be spewing out code in no time.

Assembly Language produces the fastest and most compact code. It also allows you access to every function in the micro.
If you were writing programs that worked with floating point math then "C" would be much easier but just toggling pins can be done in assembler with ease.

Just to get you started.
http://www.avr-asm-tutorial.net/avr_en/

regards
bugwhiskers

[Tinkerer]

ATMEL and assembly

Hi Tinkerer and Sean,

I remember those days Sean, my first was the Sinclair ZX80 and I spent hours pouring over the Z80 opcodes, even memorised a lot of them.

Tinkerer, if you look through the SD2000 full schematics thread you will see a downloadable file that I posted there that performs all the timings. With minor modification the code can be changed to suit any ATMEL micro and is a good starting point requiring only minor changes to the code to suit your application.

One or the benefits of going down the ATMEL path is

http://www.avrfreaks.net/

Once you join the forum you can have any question answered by a host of experts. You'll be spewing out code in no time.

Assembly Language produces the fastest and most compact code. It also allows you access to every function in the micro.
If you were writing programs that worked with floating point math then "C" would be much easier but just toggling pins can be done in assembler with ease.

Just to get you started.
http://www.avr-asm-tutorial.net/avr_en/

regards
bugwhiskers

Thanks for the encouragement, Bugwhiskers, and thanks for posting the timing schedule.

These links really look enticing. The day may come when I will know enough to be able to really compare PIC and ATMEL.

In the meantime I would love to see an educated discussion by more knowledgeable people than myself, of the advantages and disadvantages of each kind.

All the best

Tinkerer

[Sean_Goddard]

Hi Bugwhiskers, Tinkerer, all...

You COULD use C for the signal evaluation part, then have the timing loops written in assembler. A countdown/ reload sequence for the critical timing using the AVR's (or PIC's) counter timer registers works well.

Tinkerer have you tried PROTON BASIC? VERY easy to learn and the interrupt routines are pretty fast enough for a 1K pps PI with a 10uS sampling delay .

Bugwhiskers, did you read my post about the CCD delay idea? An thoughts on whether that might be useful of not?

Nice to see you are still around here somewhere . Like I said, When you have something that is usable, I'll buy one, just let me know when it's reay please.

Good luck.

[Tinkerer]

AVR or PIC?

Hi Bugwhiskers, Tinkerer, all...

You COULD use C for the signal evaluation part, then have the timing loops written in assembler. A countdown/ reload sequence for the critical timing using the AVR's (or PIC's) counter timer registers works well.

Tinkerer have you tried PROTON BASIC? VERY easy to learn and the interrupt routines are pretty fast enough for a 1K pps PI with a 10uS sampling delay .

Bugwhiskers, did you read my post about the CCD delay idea? An thoughts on whether that might be useful of not?

Nice to see you are still around here somewhere . Like I said, When you have something that is usable, I'll buy one, just let me know when it's reay please.

Good luck.

Sean,
thanks for the help.
I looked at the PROTON BASIC site and I don't like their sales tactics.
I got the timing under control now.
It is time to move on to the signal evaluation part now.

All the best

Tinkerer

[bugwhiskers]

Hi Tinkerer,

The following link may help you make your mind up.

http://search.digikey.com/scripts/Dk...EGA128A1-AU-ND

Event system to handle and prioritise interrupts
DMA
12 bit DAC's
12 bit ADC's
31nS per instruction @ 32 MHz
8 * 16 bit counters
2 * 2 analog comparators etc etc etc

All for less than 10 bucks.

regards
bugwhiskers

[bugwhiskers]

Hi Sean,

I did a search on "CCD delay" and it just returned the 2 references in this thread.

regards
bugwhiskers

[Aziz]

I can not recommend the PIC µC family. Particularly the paging on the PIC is quite inefficient. To avoid this, use only PIC18, PIC24 or dsPIC. The latter have a linear memory architecture.

If you want to use a real RISC µC, use the Atmel ones. They are darn cheap and easy to get. They have a better computation power (four times better than on a PIC with equal clock frequency).

To ensure better and accurate timings, use only a stabilized external crystal oscillator. Do not use the internal RC oscillator of the µC.

Aziz

[Tinkerer]

AVR or PIC?

Bugwhiskers and Aziz, thanks for the recommendations.

Will anybody stand up and defend the PIC?

Tinkerer

[Götz von Berlichingen]

Bugwhiskers and Aziz, thanks for the recommendations.

Will anybody stand up and defend the PIC?

Tinkerer

*stands up and waves a Microchip flag*

Honestly, i heard Atmel Stuff is not bad.
Use whatever you like, I prefer PICs and HiTech-C.

[Tinkerer]

AVR or PIC?

*stands up and waves a Microchip flag*

Honestly, i heard Atmel Stuff is not bad.
Use whatever you like, I prefer PICs and HiTech-C.

Thanks for the input.
I believe both are good. It is probably a matter of personal preference.

Would you be so kind to explain the reasons WHY you prefer PIC's?

Tinkerer

[Götz von Berlichingen]

Thanks for the input.
I believe both are good. It is probably a matter of personal preference.

Would you be so kind to explain the reasons WHY you prefer PIC's?

Tinkerer

Well, i learned about PICs first, got some free samples from Microchip
and learned to use them.
Now I'm too lazy to learn about AVRs.
There could be one Reason to use Atmel Products :
there is an open source USB Stack, no special Hardware needed... cool.
I found nothing like this for PIC - and the USB-PICs are not cheap.
Oh, and the 1 Instruction / clock cycle thing *sigh*
as far as i know, even the PIC18 need 4 clock cycles for 1 instruction.
Well, until now i needed no USB and PICs were fast enough for me.

My next Project : a stuart2 PI... first the Original, later some extra Stuff.
One or more S&H Circuits (somehow like Bugwhisker's old Design)
and the PICs A/D (10Bit) might be worth trying.

[Tinkerer]

PIC or AVR?

Well, i learned about PICs first, got some free samples from Microchip
and learned to use them.
Now I'm too lazy to learn about AVRs.
There could be one Reason to use Atmel Products :
there is an open source USB Stack, no special Hardware needed... cool.
I found nothing like this for PIC - and the USB-PICs are not cheap.
Oh, and the 1 Instruction / clock cycle thing *sigh*
as far as i know, even the PIC18 need 4 clock cycles for 1 instruction.
Well, until now i needed no USB and PICs were fast enough for me.

My next Project : a stuart2 PI... first the Original, later some extra Stuff.
One or more S&H Circuits (somehow like Bugwhisker's old Design)
and the PICs A/D (10Bit) might be worth trying.

Thanks for the explanation. This really makes sense. I will stick to the PIC for this project, but will be looking around for the next project.
As for the the writing of code? I make myself no illusions. I can manage some very simple stuff but for more advanced code I will need help.

Tinkerer

[Tinkerer]

PIC or AVR

Gotz Von Berlichingen,

Do you feel like trying your hand at writing some code for my discriminating PI?
I have a PIC 16F690 and a PIC 16F877 and programming and debugging capability for them.

I have also downloaded the AVR Studio to have a look at it for future applications.

Tinkerer

[Götz von Berlichingen]

Gotz Von Berlichingen,

Do you feel like trying your hand at writing some code for my discriminating PI?
I have a PIC 16F690 and a PIC 16F877 and programming and debugging capability for them.

I have also downloaded the AVR Studio to have a look at it for future applications.

Tinkerer

Your discriminating PI ? Is this Project here on Geotech ?
I will be busy the next few Days, have Work to do.
I'm not a great Programmer, but willing to help and
i have a few 877 and 877a for testing.
What exactly should the Program do ?
Is this Thread the proper Place to discuss it,
or should we take it to Private Messages or a new Thread ?

[Tinkerer]

Discriminating PI project

Your discriminating PI ? Is this Project here on Geotech ?
I will be busy the next few Days, have Work to do.
I'm not a great Programmer, but willing to help and
i have a few 877 and 877a for testing.
What exactly should the Program do ?
Is this Thread the proper Place to discuss it,
or should we take it to Private Messages or a new Thread ?

Carl has kept this forum going for ten years.
We all should show our gratitude by posting interesting subjects.
So I propose we make this an "Open source" project.
At least the "demo" mode.
Tinkerer