[dba-Tech] OT: Is anyone into controllers?

Lembit,

I thought of you when I posted this, knowing that you had been working on
controlling your new home. 

If you are just getting started using the PIC I would highly suggest that
you at least consider switching to the Atmel.  The prices are about the same
but the ATMEL AVR is a completely modern architecture and doesn't have the
2kByte program space issue that the PIC has.  Plus it is supposed to be much
faster as all instructions execute in one clock cycle, so an 8 MHz device is
8 MIPS.  As I mentioned, I started by looking at the PIC but when I found
the Atmel AVR I was hooked.  

You can get devices (though certainly not the hundreds of choices you can
find in the PIC) ranging from low end up to 128KBytes program space.

http://www.atmel.com/dyn/products/param_table.asp?family_id=607&OrderBy=part
_no&Direction=ASC

Depending on the uC selected, the controllers I am using can have built in
UARTs, as well as 1 wire (a misnomer) comms which are often more useful that
UART in uCs.  These are cool little widgets.  The one thing they seem to be
missing that you can get in the PIC are D to A converters, though with
built-in PWM stuff you can use a PWM output and a filter to build a D to A.

Given the prices, 

http://www.jameco.com/webapp/wcs/stores/servlet/CategoryDisplay?storeId=1000
1&catalogId=10001&langId=-1&categoryId=106010
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&sto
reId=10001&catalogId=10001&productId=204089&pa=204089PS

(and you can get them even cheaper over on Digikey) I am looking at building
functional blocks where little uCs each do one thing and they talk to each
other over 1 wire.  For my project I need a couple of PWM motor controllers
talking to a central machine controller.  The motor controller software
could be run on the machine controller, or a little 20 pin uC could be
placed out on a motor controller PCB with everything required to completely
run a motor (Hbridge power MOSFETs circuits and the PWM micro), then it
could just receive commands from the central controller - direction, speed
and softstart ramp time - as instructions sent over the 1 wire interface.

Assembly language is indeed easy, in fact way easier than 'C' to get started
in.  The biggest problem is that you have to really get into the instruction
set and pneumonic for assembler whereas C shields you from that.

There is a freeware C compiler that is available for my uC family.  

http://gcc.gnu.org/

If you stick with the PIC you might see if it is available for that as well.
In the Atmel toolset it was a breeze to get set up and integrated into the
IDE.

I have my first C program running:

#include <avr/io.h>
#include <util/delay.h>
void wait(void);
int main (void)
{
// set PORTD for output
DDRD = 0xFF;
while(1)
{
	for(int i = 1; i <= 128; i = i*2)
	{
		PORTD = i;
		_delay_loop_2(30000);
		}
			for(int i = 128; i > 1; i -= i/2)
			{
			PORTD = i;
			_delay_loop_2(30000);
		}
	}
}

Anyway, I am glad to hear you are into this and let's talk.  This is going
to be a lot of fun.  Makes me wich I was retired so I didn't have to do real
work.  ;-)

John W. Colby
Colby Consulting
www.ColbyConsulting.com

-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Lembit Soobik
Sent: Monday, September 25, 2006 4:05 AM
To: Discussion of Hardware and Software issues
Subject: Re: [dba-Tech] OT: Is anyone into controllers?

YES, yes, here!

I have been working since a few weeks on this and finished a program which
reads from my EIB bus and displays the results on a 2 x 16 LCD. Things like
Window in basement is open or such.
It was pretty easy to get started.
I am using assembly language and am surprised how easy it was.
I have still a lot of plans with this and things that I have not found a
good answer for, like communication with a PC,...

I am using Microchip. I have got the ICD2 (debugger) and PICDEM 2 PLUS demo
board, which I am using for programming.
I have buildt the circuit hardware with one of these universal boards. have
not yet made a pc-board.

Right now I am building an Access db, which reads the .asm file and modifies
it to insert customized message-texts.

Microchip has forums and also a 7/24 support group (free).

I am interested in participating in your forum.

Lembit