Which object is best for doing Prop-to-Prop communications?

ElectricAye

I'm planning a project in which one Prop will serve as the bossman and maybe about 4 other props will serve as employees. Data will need to flow both ways. I know there are a number of objects on the OBEX that look like they will work but I was wondering which ones are best for a perpetual newbie? After looking through the OBEX protocol objects, I've noticed the following:


obex.parallax.com/objects/546/

obex.parallax.com/objects/397/

obex.parallax.com/objects/183/

I know nothing about serial communications, etc. so I need to take this on one baby step at a time. Any suggestions will be greatly appreciated.

thanks,
Mark

ElectricAye

The silence here has been shopvacuuming my brain. Am I to conclude that enslaving 4 Props to a single master Prop is impossible?

Cluso99

Firstly, are you sharing the lines or do you have 2 lines (pins) for each employee and 4x2 lines (pins) for the bossman?

What speed do you need?

How many cogs are available on the bossman?

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

ElectricAye

Cluso99 said...
Firstly, are you sharing the lines or do you have 2 lines (pins) for each employee and 4x2 lines (pins) for the bossman?

What speed do you need?

How many cogs are available on the bossman?

Cluso,

At this point I don't know what I need. I guess I will make available whatever number of pins are needed to get one Prop to talk to about 4. The 4 slaves will be spaced around a bench about 1 or 2 meters (3-6 feets) from the master. The speed is not critical. It's an automation application that needs to command new processes to take place no more than every 10 seconds or so. It's basically an array of syringe pumps driven by stepper motors, so they don't move very fast. I'm thinking of using a master prop to run a VGA, mouse, and real time clock and to have it give cues to the ~4 slave props that will actually do the micromanagement of the syringe pump activities. I don't even know where to begin on something this complicated. But the over-arching force of nature in my design is this: I've got to do it as cheaply as possible. In fact, I'm designing the syringe pumps from scratch and the end result has to work like a charm but at back-room ghetto prices.

At this point, everything is up in the air and I don't have a clue. I'm looking for suggestions on just where to start.

thanks,
Mark

Peter Jakacki

Use RS485 to physically connect all the nodes that you want, whether they are on the same bench or down the road. I'm feeling the pressure to finish and release my UNICOM object which will take care of most serial communications requirements including networking devices. Your application needs to know how to reference these "devices", I prefer making it transparent as to where they are physically located, they could even be on the same Prop chip or down the road. This way you application itself does not have to worry about the physical implementation so that you can use methods to access I/O for instance, rather than trying to say OUTA or INA which assumes it is always local (and limited).

If anyone has any thoughts on the API for networking then could you do this through the UNICOM thread http://forums.parallax.com/showthread.php?p=867266

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*Peter*

kwinn

I have used this one by Tim Moore (based on the full duplex serial object by Chip Gracey) " http://obex.parallax.com/objects/340/ "

It supports 4 ports using one cog, works very well, and I found it as easy to use as the FDS object. You could use it for the boss and workers to keep things simple, and it will work with 2 pins per port for no handshaking or 4 pins per port with RTS/CTS.

Cluso99

With the distance of 1-2 meters and the fact there may be inherrent EMI noise, I would go with RS485 as Peter has suggested. This way you will use a cog to drive the port and each prop will just be multidropped from the same cable.

Peter is now the best one to advise. But for the beginning you can use close props and serial to get the rest running.

BTW: No replies in 5 hours. Maybe you should try other forums??

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Links to other interesting threads:

· Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
· Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

ElectricAye

Cluso99 said...
....Maybe you should try other forums??

What? .... you mean... this isn't the only one?! There might be others?


Thanks for the advice, everyone. I just needed some kind of sanity check/ product endorsement before I proceed. I'll take kwinn's suggestion and attempt that simple serial first.