help calling spin from assembly

madjack

Hello
I am new to spin and assembly programming and I’m having some difficulty with calling
back from assembly to spin.
My first program here is a hyper terminal connection in spin that loads and starts an assembly program that runs a stepper motor driver. The drives I am using are geared and are also micro stepping at 2000 resolution.· It takes 6000 steps to get one full revolution of the step motor. This drive can ramp up to a high frequency and back down & stop. It works fairly well but I need it to call back to spin at the end of the drive so that hyper terminal can tell the parent system the drive is completed, then reset the propeller. This call back is were my problem is.
To load the assembly code, with hyper terminal connected you need to;
1.)·Send an integer representing the pin the modulated out put will be on
2.)·Send a value between 1 & 79 to set a ramp, 1 = slow 79 = real fast
3.)·A value in steps from 10 to as high as the system can count representing steps
4.)·And a 1 or a zero for motor rotation that is an output at pin 0
····· All entrees followed by carriage returns
The system expects 57600 baud & no hand shaking via the “Full Duplex Serial Plus” object.
Thanks in advance to anyone willing to look at my code
Jack

Mike Green

In Wait in the spin code, you have "while bizy := 0". This should be "while bizy == 0"

madjack

Hello Mike
· I have tried it both ways and it still get hung up ·in “Wait”
I must have more problems in my code that I can’t find
·Thanks for looking at it
Do you have any other thoughts?

I just cant find what I have done and have little experiance with spin & assembly.

Jack

Ariba

Your _finished pointer in the Assembly code points to csteps and not to cfinished, because you don't read csteps in the initialization.
Try it with this change:
add p,#4
rdlong _finished,p
to
add p,#8
rdlong _finished,p


Andy

madjack

Muchas grassias Mr. Ariba
That was it.
I still need a little delay before the reboot so that hyper terminal can
Get a full “done” flag.

Thank you all for your help

Jack

StefanL38

Hello Jack,

of course as a theme for itself, it could be very interesting how to get back from assembler to SPIN.

hm - to me it seems very strange why you want to REBOOT the propeller after EACH SINGLE stepping-command ??

could you explain the advantage ?

I would implement an idle-mode. The driver-cog is started at the beginning and remains in idle-mode

then the interface-cog setups the details pin, lowSp, ramp, rampInc, steps
and finally sets another flag for "GO"

then interface-cog is waiting for the flag "finished"

the driver-assembly-cog waits for the flag "GO".
If "GO" received, generates the stepping-signals.
After finishing, sets the flag "finished and returns to idle-mode

cognew takes some time because 2kB of RAM has to be copied from HUB-RAM to COG-RAM and AFTER that the cog can start working

REBOOT takes some SECONDS because the propellerchip has to to his FULL bootsequence.
If you want to drive more than one "stepline" in sequence it will be interrupted be the reboots
and that's what i do not understand at all

The flags "GO" and "finsihed" are just another two longs defined in sequence to pin, lowSp, ramp, rampInc, steps
that you can easyly access them from assembler

So please tell me what is the advantage of all the cognews, and cogstops and the rebooting ?

best regards

Stefan

Post Edited (StefanL38) : 3/31/2008 9:37:09 PM GMT

madjack

·

Hello Stefan

Thanks for the input. Any and all input is welcome as I wish to learn this technology.

I don’t have a good reason for stopping the cog and rebooting other than it is a short cut to get back to the start of my program. As I gain more ability with spin and assembly programming I will no doubt want to explore and add to this but at this point I’m struggling to crawl. Walking will have to wait until I get the bugs out of crawling.

The current application I would like to lend this first program to would not be very demanding of the propeller as the equipment already has a control system. At this point I just need the propeller to be ready to modulate one out put at a time and flag the parent system when it has finished a drive sequence.

I do wish to gain the ability to control 2 & 3 axis at a time and create circular and other more complex moves. But for now I am going to have to step on my tail a little.

If you see anything else that seems odd please show me the way.

I will listen to all of it.

Jack

StefanL38

Hello Jack,

ah now i can see. OK that's one way to go.

i think to code an idle mode will be easy for you just compare to values if not zero jump back to loopstart
if zero "GO"

To move 2 axis at the same time you can use the "Bresenham-Algorithm"

The "Bresenham-Algorithm" needs only addition and substraction of INTEGERs to calculate everything
it does NOT need multiplication or division or floating-point-calculation

by googling i found this PDF

www.khwarzimic.org/takveen/helix.pdf

there are o lot more hits for this keyword

Also search the propellerforum about steppermotors

search.parallax.com/search?q=+%2B%22f%3D25%22&btnG=Google+Search&client=parallax&lr=&num=100&output=xml_no_dtd&site=parallax&ie=&oe=&sort=&proxystylesheet=parallax

best regards

Stefan

madjack

Thanks Stefan
I'm a little slow so this may take soon time as I also have to juggle a few other situations
I will more than likely post more questions to this thread in a week or so
Or start another one

Stefan
I want to try all the suggestions you have given

Thanks to all as other posts as well have been a huge part of my learning

Best regards to all

Jack