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grasshopper
03-19-2009, 03:14 AM
So I am designing another board using the propeller and I need some input. The boss is really pushing my limits as well as the propellers.

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Post Edited (grasshopper) : 4/10/2009 2:44:54 AM GMT

Cluso99
03-19-2009, 03:28 AM
I woud just use 2 props linked serially (2 pins) or parallel with handshake (10 pins). Alternately you could use i2c bus extenders, latches or another micro.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBladeProp (http://forums.parallax.com/showthread.php?p=786418), SixBladeProp (http://forums.parallax.com/showthread.php?p=780033), website (Multiple propeller pcbs) (http://bluemagic.biz/cluso.htm)
· Prop Tools under Development or Completed (Index) (http://forums.parallax.com/showthread.php?p=753439)
· Emulators (Micros eg Altair, and Terminals eg VT100) - index (http://forums.parallax.com/showthread.php?p=778427)
· Search the Propeller forums (via Google) (http://search.parallax.com/search?site=parallax&client=parallax&output=xml_no_dtd&proxystylesheet=parallax&proxycustom=<HOME/>&ie=&oe=&lr=)

My cruising website is: ·www.bluemagic.biz (http://www.bluemagic.biz)·· MultiBladeProp is: www.bluemagic.biz/cluso.htm (http://www.bluemagic.biz/cluso.htm)

RiJoRi
03-19-2009, 03:28 AM
Take a look and see if any of your current chips have chip select lines. You may be able to use the same Data I/O lines for them. Also look into a 74xxx138 decoder, or its modern equivalent. At work a serial-parallel converter was used to create an 8-bit output port using 3 pins for data, clock, and output enable. You should be able to use a similar setup for input.

--Rich

Joms
03-19-2009, 03:41 AM
I would recomend using a serial to parallel IC for easy things like LED and LCD displays. I would also look into possibly using a serial stepper motor driver. They allow you to send a serial command at the unit will continue to run the stepper motor for you until is sees another speed or direction command. Look around in the Parallax store.

I am sure someone else is chime in with a few other ides better then mine on some of the data bus questions. I have just had really good luck with serial to parrallel and parrallel to serial IC's.

Joms
03-19-2009, 04:03 AM
Here is a link to those drivers I was thinking about...

http://www.parallax.com/tabid/160/List/0/CategoryID/35/Level/a/Default.aspx?SortField=ProductName,ProductName

I forgot you can actually buy a stepper motor that will allow you to connect serial directly to it. After thinking about this, my plan would probably cost a little more then other suggestions though...

JRod1
03-19-2009, 05:51 AM
I use a EDEFT609 available from Jameco for $11.99 to control a stepper motor. It's a small 8 pin dip package and requires only 1 I/O pin from your propeller. It supports several commands such as ramp up/ramp down, single step, etc.

grasshopper said...
@ Cluso99:
Your suggestion is by far the easiest approach and I will go that route if I cant achieve another.

@ RiJoRi:
This is something I over looked. Thanks for the heads up.


Joms said...
I would recomend using a serial to parallel IC for easy things like LED and LCD displays. I would also look into possibly using a serial stepper motor driver. They allow you to send a serial command at the unit will continue to run the stepper motor for you until is sees another speed or direction command. Look around in the Parallax store.

I am sure someone else is chime in with a few other ides better then mine on some of the data bus questions. I have just had really good luck with serial to parrallel and parrallel to serial IC's.


Excellent Idea Ill see if i can get my fingers on a serial stepper motor driver.

Thanks for the ideas fellas.

Timothy D. Swieter
03-19-2009, 07:13 AM
Why have a RS-232 connection and a USB connection. Those two interfaces could be combined into one or the other for programming and data/controlling purposes. That would free two I/O pins.

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Timothy D. Swieter, E.I.
www.brilldea.com (http://www.brilldea.com) - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com (http://www.tdswieter.com)

Timothy D. Swieter
03-19-2009, 11:36 AM
There is another thread recently that talks about using other low cost micro in system. It is a neat concept: http://forums.parallax.com/showthread.php?p=791504

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Timothy D. Swieter, E.I.
www.brilldea.com (http://www.brilldea.com) - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com (http://www.tdswieter.com)

Bill Drummond
03-19-2009, 02:28 PM
Anyone have experience with a pic ? Maybe a prop and a pic would get the job done. I have a pic programmer and a compiler but have no clue how to program a pic.

The PIC comes in many flavors from 8· to 40 pin chips.Try this link for a starting point··http://www.awce.com/app3kit.htm·you can get proto boards from Jameco and Sparkfun .... download the data sheets from Micrchip. Also http://www.mikroe.com/·for a serious development system.

MagIO2
03-19-2009, 03:25 PM
Why would you like to use a PIC? You now talk about writing SW in two worlds. And multitasking in common microcontroller-designs is not easy - not to say it's a pain in the a... . You would have to use Interrupts.
Either I'd follow clusos advice or build a port-expander around the Prop.

Clusos solution also means more 'horsepower' and you are flexible. The code you wrote for the Motor drivers will work on both Props.
Port expanders can be implemented with serial to parallel converters or you can have a look at CPLDs. To know something about boolean expressions is enough for building a port expander. Software to program CPLDs is for free and a interface can be build with only a few cheap parts.

Timothy D. Swieter
03-19-2009, 03:27 PM
You could build a serial to parallel interface for the 2x20 or get a 2x20 with a serial interface. The LM9033A is a graphical LCD on Brilldea that has a serial interface. It isn't 2x20, but it could do more than a 2x20 if your packaging/design allows for a screen change.

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Timothy D. Swieter, E.I.
www.brilldea.com (http://www.brilldea.com) - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com (http://www.tdswieter.com)

Leon
03-19-2009, 06:26 PM
That sort of application might be better suited to a different controller, like the LPC2148 ARM chip. That should easily cope with all that, in a single tiny 64TQFP package costing under $5 in quantity. I have an LPC2148 controlling a medical instrument prototype with a similar amount of I/Os.

Leon

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CannibalRobotics
03-19-2009, 11:50 PM
Look at how you can share clock lines on your serial devices. I saved a bunch of ports by sharing a single clock line between several ADCs and SIPO. That's what chip select lines are all about. Also look at the old workhorse of addressing, the 74x138 series. In 3.3v 16-SOIC package it's a MM74HC138. It's a 3 to 8 line decoder that can consolidate your chip select lines. It also provides some gated inputs to cascade easily get 4->16.
Look at the SN74AHCT595DBR (74x595 series) Serial in, Parallel Out shift register. With the speed of the prop vs things like stepper motors you can ship all of your stepper control out through 2 or 3 lines. They can be cascaded so sending an entire 32 bit long is about 20 asm instructions. You can clock them well above the speed capabilities of the prop.
For input, check out the 74x597 series. It's like a mirror image ot the 595 about but it's PISO to you can sample a bunch of inputs at a very high rate. 32 inputs for 3 ports.
Jim-

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dMajo
03-20-2009, 02:04 AM
grasshopper said...

Timothy D. Swieter said...
Why have a RS-232 connection and a USB connection. Those two interfaces could be combined into one or the other for programming and data/controlling purposes. That would free two I/O pins.


True but our product offers a usb or serial connection. Some older system use serial while some newer system sue usb.


Two pins is enuogh for them both. Prop TX in parallel to both, the two RX through a "single gate IC" (or 2 transistors)·to Prop RX. You will transmit to both ports but can receive from one at a time

Cluso99
03-20-2009, 02:32 AM
Grasshopper:

Take a look at this thread "TriBladeProp" http://forums.parallax.com/showthread.php?p=786418 for schematics, photos, etc, of what I have done with three propellers and this thread "Single Board Computer with the TriBladeProp" http://forums.parallax.com/showthread.php?p=790917·- it might give you some ideas of how simple it is to use multiple propellers.

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBladeProp (http://forums.parallax.com/showthread.php?p=786418), SixBladeProp (http://forums.parallax.com/showthread.php?p=780033), website (Multiple propeller pcbs) (http://bluemagic.biz/cluso.htm)
· Single Board Computer·using the TriBladeProp board (ZiCog Z80 Emulator) (http://forums.parallax.com/showthread.php?p=790917)
· Prop Tools under Development or Completed (Index) (http://forums.parallax.com/showthread.php?p=753439)
· Emulators (Micros eg Altair, and Terminals eg VT100) - index (http://forums.parallax.com/showthread.php?p=778427)
· Search the Propeller forums (via Google) (http://search.parallax.com/search?site=parallax&client=parallax&output=xml_no_dtd&proxystylesheet=parallax&proxycustom=<HOME/>&ie=&oe=&lr=)

My cruising website is: ·www.bluemagic.biz (http://www.bluemagic.biz)·· MultiBladeProp is: www.bluemagic.biz/cluso.htm (http://www.bluemagic.biz/cluso.htm)

RiJoRi
03-20-2009, 04:32 AM
grasshopper said...
Thanks for the advise all.

I can see that I have the same thoughts that many of you mentioned. I guess it boils down to making a choice and going with it. Part of my job is trying to predict the future (expansion) and this is the toughest part. I think that going with another prop. Two would cure my issues but its over kill.


The sad voice of experience tells me that in time, what seemed like overkill can be seen as the forethought of a genius. I won't give the grizzly details, I'd depress the whole board here...

--Rich