Propeller Newb questions

Dgswaner

Ok I haven't had the prop for even a week so I'm a Newb, I'll have plenty of time to prove I'm a noob later.

I have the prop. demo board, what is the Max current an I/o pin can handle.

I want to drive some 5v relays, so I'm guessing I'll have to use transistors, will the 5v, pin be sufficient to handle 4 relays at once? or do I need to incorporate an additional power supply.

Can some one provide a link or spin code for controlling a servo, or preferably a demo on how to connect and operate, I've looked at the object exchange and downloaded the 4 servo controller as well as the 32 servo controller, but I want a strip down version of it, I want to figure out how it works and what is required, being new to all of this the many layers of "features" are a little hard to plow through. It just seems odd that what can be done on a stamp in 2 line takes a hundred for the prop. I know thats not comparing apples to apples but for a beginner it seems a bit much.

thanks

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

deSilva

I should recommend you:
- read the Data Sheet
- thoroughly read the first 4 Chapters of the Manual
- work yourself through the Educational Examples.

Believe me - it will pay! Do advanced things later.

ALIBE

deSilva
I hate to say this but, that does not help answer the simple and understandably important questions any newb would have. One of the reasons why we have these forums is "ask away". Sometimes, that is the easiest and best route for quickly ramping up. When you start saying things that sound like, do THIS first THEN you can think about THAT later (not the first time), has (in my case) and might switch people off. And, that is not a good motivational catalyst.


I love the great work you're doing on propeller and contributing; I appreciate all of that. But, please note there are folks who will need ground level to-the-question help and guidance.

I have read thru the Manual - it is good material - not sufficient enough to help ramp people up. BS-II Manual is a lot better starter document than the Prop manual is from a beginner perspective. That's my honest feedback to the Parallax Prop teams. I have always voiced the limited content in the maual - it is mostly a command reference (which is good to have) than it is a starter manual.

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"any small object, accidentally dropped, goes and hides behind a larger object."

·
ALIBE - Artificial LIfe BEing. In search of building autonoumous land robot

deSilva

@Dgswaner: Sorry if my answer sounds to some people as "demotivating". I have diffuculties with the English languages from time to time, but - as a member here mentioned some days ago - there are also "cultural" differences. It seems more appropriate in ango-saxion countries to give specific answers to specific requests, without challenging the background. In continental European - maybe especially German influenced - cultures there is much more stress on an "educational approach": Help them find it by themselves.

Many of the "questions" in this forum can be answered by RTFM. If the answer IS plainly that, I personally think you should give it, maybe also giving the section or page number. I know this a very personal opinion, but I do not think you can DO programming or electronics by following receipes: You have to UNDERSTAND.

My reason for posting here for monthes now is to further this UNDERSTANDING, as I notices that over and over the same problems were addressed and incompletely answered.... I have no problems in being tacit in case of what I called "simple specific requests"....

@ALIBI: I appreciate your posting, and I must say I have not fully been aware of possible touchinesses, although I met this issues before in this forum as you also remarked.
But please note: I did not recommend "the Manual" but "the first four chapters or the Manual"
I also ask myself, why YOU did not give Dgswaner the mA he was asking for??

hippy

Dgswaner said...
I have the prop. demo board, what is the Max current an I/o pin can handle.

From pages 15 and 16 of the Propeller Manual (version 1.01), each I/O pin can source or sink 30mA.

There's also a stated limit for each group of 8 pins ( P0-P7, P8-P15 etc ) of 100mA, so if one pin is sinking 30mA, the rest can only sink 70mA between them, and so on. If you needed a number of higher current sinking or sourcing pins you might have to spread them across the four sets of eight pins.

However ... from page 4 of the Propeller Datasheet (Rev 0.3 5/17/2007), the figure there is given as 40mA per pin. On page 25, that 40mA is repeated as an Absolute Maximum Rating.

The Spin Stamp Manual (v1.0 04/2007), also repeats the 40mA figure, and also adds "all output pins together must not exceed 300 mA when in sink and source states", referring to P0-P15, suggesting 150mA max per eight pins, not the 100mA given in the Propeller Manual.

So, good question, no easy answer.

Dgswaner

well I opted to not have the prop demo board power the servo just to be safe, and I got it working. but I'll still need to do some figuring and see how much mA is required for each relay, and go from there.

I did get the servo4 object working, got to love objects! so I guess at this point I don't need any more info on servos.

I do miss the debug to a serial port feature of the stamps, as I have no extra Tv, monitor or LCD's handy. so for reading inputs I'm going to have to rely on LED's to let me know what's going on.

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

deSilva

Dgswaner said...
I do miss the debug to a serial port feature of the stamps, as I have no extra Tv, monitor or LCD's handy. so for reading inputs I'm going to have to rely on LED's to let me know what's going on.

No, You have not
There are (at least) two very good helpers:
- Ariba's "PropTerminal"
- The fancy "ViewPort"

hippy

Dgswaner said...
got to love objects ... I do miss the debug to a serial port feature of the stamps

An object which bit-bangs out serial will give you that ( P30 via the ProPlug/Clip or any other pin ). Checkout the object exchange, and deSilva points to some more powerful and impressive solutions.

Ken Peterson

@deSilva: First of all, I would like to point out that I agree with you about educating people. I hate to just give people the short answer. I prefer to help them understand where the answer comes from, so they can help themselves later. "Give A Man A Fish, Feed Him For A Day. Teach A Man To Fish, Feed Him For A Lifetime". You can't design a robot without doing some studying first.

It's unfortunate in this world of "instant gratification", that there is so little patience. For many people, picking up the manual and reading it through before you begin is a daunting task. They need help understanding that the big fat book is nothing to be afraid of. I read the Propeller Manual from beginning to end (well...mostly) before I even bought one, but I'm weird that way.

I believe the best approach is this:

1. Give them a short answer to their question, but do not do any design for them (unless you really want to).
2. Tell them where they can learn more "for more about this, read pp. 12-15 in the manual".
3. Give them strong, but polite encouragement to study the books before trying to solve complicated problems.

Don't forget: a good teacher is also a good listener!

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The more I know, the more I know I don't know.· Is this what they call Wisdom?

deSilva

mirror

deSilva said...

Dgswaner said...
I do miss the debug to a serial port feature of the stamps, as I have no extra Tv, monitor or LCD's handy. so for reading inputs I'm going to have to rely on LED's to let me know what's going on.

No, You have not
There are (at least) two very good helpers:
- Ariba's "PropTerminal"
- The fancy "ViewPort"

- or - SerialMirror (in the object exchange) for sending serial messages from multiple objects.

Dgswaner

thanks for all the help guys, that is a lot of what makes this product so great. I'm not the type that can sit and read 300 pages of command syntax and descriptions, the only thing that will do for me is get me a ton of sleep and tell me what the prop is capable of which in it's self may be worth the effort. I have to learn by doing, so I much prefer the How to manuals build somethings big one step at a time.
I must have been up too late when I tried to access the Education pages, I swear it downloaded a something.PE file and I figured that it was only for educators... I will go through those lesson before I try anything on my own.

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

Steph Lindsay

Hi Dgswaner,

The Propeller Education Kit Labs aren't for educators only, they are for anyone who wants to be educated!· Andy has written them for a college-level audience·with some·programming and electronics experience, but no prior knowlege about the Propeller.· By following the labs you can learn by doing, though you will have to adapt them to the Propeller Demo Board, since the labs are written for the fully-breadboard PE Kit.· You can access a thread about each of the labs from the PE Kit sticky at the top of this forum, and if you have questions or feedback on any of them just post them there and the author will reply.

-Stephanie Lindsay

Editor, Parallax Inc.

P.S. to Alibe,

Thanks for your feedback about the BASIC Stamp and Propeller manuals; your points are well taken.· While they share the same primary author, the BASIC Stamp Manual has been revised, expanded and refined several times over many years.· Were we to have tried to make the Propeller Manual everything we want it to be in its first edition, it would not be published yet!·· There are plans for revisions in the works but no dates at this time.

Dgswaner

Thanks Stephanie, I made it through the I/O lab it was very informative. I downloaded the video clip, but it didn't have an extension so I assumed it was a video clip and tried guessing the file extension. I later figured out it was a zip file containing the WMA file. I got it all worked out and all is well. and I look forward to more.

thanks for all your work on them.

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

Paul Baker

The data provided in the manual was from before the chip was being fully characterized, the Prelim datasheet is a more accurate representation of the situation. Thanks for pointing out the difference, I'll make a note for the manual to be updated when it is time for it's next revision.

hippy said...

Dgswaner said...
I have the prop. demo board, what is the Max current an I/o pin can handle.

From pages 15 and 16 of the Propeller Manual (version 1.01), each I/O pin can source or sink 30mA.

There's also a stated limit for each group of 8 pins ( P0-P7, P8-P15 etc ) of 100mA, so if one pin is sinking 30mA, the rest can only sink 70mA between them, and so on. If you needed a number of higher current sinking or sourcing pins you might have to spread them across the four sets of eight pins.

However ... from page 4 of the Propeller Datasheet (Rev 0.3 5/17/2007), the figure there is given as 40mA per pin. On page 25, that 40mA is repeated as an Absolute Maximum Rating.

The Spin Stamp Manual (v1.0 04/2007), also repeats the 40mA figure, and also adds "all output pins together must not exceed 300 mA when in sink and source states", referring to P0-P15, suggesting 150mA max per eight pins, not the 100mA given in the Propeller Manual.

So, good question, no easy answer.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

_Mark

Dgswaner said...
I downloaded the video clip, but it didn't have an extension so I assumed it was a video clip and tried guessing the file extension. I later figured out it was a zip file containing the WMA file.

I've noticed that same problem several times on this forum. It seems that any download attached to a post, will get its filename truncated after the first space (upon downloading it at least). This means, only attachments with filenames that do not contain spaces, are downloaded with their full name (and extension) intact. I'm not sure if this is a Firefox thing, or a problem with the forum (or both). But I do not recall having seen this problem before on another site.