Re: ATM Microcontroller based telescope driver III - More Memory

[martin.cibulski@t-online.de (Martin Cibulski)]

Thomas,

> From: "Thomas Bryhn" <thomas.bryhn@fys.uio.no>
> A and B are however selfimposed limits and it seems to me that they are in
> direct conflict with using one of the most powerful microcontrollers in
the
> AVR series.

A single sided PCB (A) is still possible because the SMD processor
is mounted on the bottom side.
And it is very small what makes a 100x80mm board (B) suitable.

> I've been  playing with the idea of a uC based telescope drive
> for a few months (without building anything) and I've envisioned a more
> modular system: One simple uC-board for each axis, taking pulse commands
> from a separate master controller. This controller also accepts standard
> serial commands from a PC (or a uC-board with database), and communicates
> with the hand control. The hand control may house a separate uC and
display.
> By breaking all up into separate boards it would be much easier to do the
> routing, it would suffice to use simpler uC available in DIP packages, and
> people could also customize or expand their system quite easily.

My first controller was modular. There was a CPU board and two boards
for the motor drivers. The layout was a little complex because I used
the parallel adress and data bus to write control bytes into registers
connected to the motor drivers. And some more chips were needed
for adress decoding and selection.
Later I thought about simpler modular designs. Instead of the adress/data
bus the ports could be connected via flat cable to the driver boards.
But all these ideas were enforced by the required cooling area for the
stepper
drivers. I always had the opinion that someone else will perhaps build
a single board system but be deterred from building 4 PCBs until
anything starts to work.

> BTW, the "TWI" from ATMEL is just another name for the I2C bus. You
> probably knew this already, but if not it could ease your search for
> suitable memory modules.
I didn't know that TWI is I2C, thank you for the hint.

Best Regards,
Martin Cibulski
http://martin.cibulski.bei.t-online.de