propeller ED kit power question

Rontopia

hi gents.

I have a power regulator that Im trying to use on the propeller ED Kit. this regulator is something that I have been working on here at the company that I work for over the last few months. its a module that we are getting ready to ship in the next few months. it takes a 12v and outputs up to 3 rails of up to 3.6v. I was given one to play with because I have a nack for finding bugs in software and .. well i can just break things[noparse]:)[/noparse] this regulator has 2 outupts that can carry up to 3A and one that can carry up to 5A. You can also watch the current and other neat stuff in real time with the software package.. anyway I got this thing on my desk and it occured to me that I could run the propeller with this.

so.. I want to be sure that I state that my ED kit is setup exactly as discribed in the Setup and Testing Lab when I started this ..

I removed componets LM2940 - 5.0 and LM2937 3.3. I then used some jumpers to plug in the 3.3v rail of my regulator in to the + - of the board. I got power no problem as indicated by the power led. I also took a volt meter and tested several places on the ED kits bread board and found I had·2.8 volts everywhere on the board.

so now the problem is why am i getting 2.8v on the board and away from the board I messure 3.3V on the regulator output rail?

the propeller plug is not working. when I do F7(identify hardware) i get propeller not found. so.. what did i unhook from power? I removed no wires.. no caps.. just the LM's. I pluged power into h5 and h4 on the bread board and like I said its set up exactly like the setup and test lab. h5/h4 is where the LM2937 3.3V hits the board and provides power.. is this a result of low power? 2.8V

thanks for the help.. I know its not a usual question.



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IC layout designer
Austin Texas

Post Edited (Rontopia) : 3/13/2008 9:50:18 PM GMT

Clemens

The sticker on the propplug must face down.
Do the leds of the propplug blink, when you try to upload a program?

Rontopia

yes once.. my laptop "pings" the prop plug

I have been using this ed kit for a year now off and on. I havent moved the prop plug and if I plug the LM's back in and hook this back up to the 9V battery like in the setup and test lab.. everything is fine.



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IC layout designer
Austin Texas

Post Edited (Rontopia) : 3/13/2008 6:03:07 PM GMT

Rontopia

ok.. something is pulling the v down to 2.8..

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IC layout designer
Austin Texas

propelleruser999

clemens,

i only got the propeller plug to work, if the logo faces up. i have the proto board.

Clemens

Yup,
Protoboard:up,
Education Kit: down.
I have both, kinda confusing sometimes.

Rontopia

so what on the ed kit would be pulling the V down to 2.8?

or do I have 2 different problems here?

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IC layout designer
Austin Texas

Rontopia

ok so I have done some more checking.. and I have found that the regulated output of LM2937 3.3 is actually 4.32. does that make sense?

so somewhere on the ed kit board about a 1V is being droped? and in case you didnt know.. thats a question because im no engineer.. so im just guess-in[noparse]:)[/noparse]



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IC layout designer
Austin Texas

Post Edited (Rontopia) : 3/13/2008 9:54:51 PM GMT

Harrison.

Are you sure your meter is good? My guess is your LM2937 is fine, and your custom regulator is incorrectly configured.

Lets do some quick calculations to see what's possibly going on here:

LM2937 measures '4.32V'
4.32V - 3.3V = 1.02V (this is to calculate your possibly bad meter's offset)

Your custom regulator measures '2.8V'
2.8V - 1.02V = 1.78V (real voltage assuming your 'bad' meter's offset is linear)

The above 'real' voltages are all common logic and core voltages. 1.8V is a common voltage used for digital logic in smaller silicon processes and 3.3V is obviously what the Propeller runs on.

So you may want to get your company's regulator checked out. You may be using one of its 1.8V outputs or something funky like that.

Post Edited (Harrison.) : 3/13/2008 10:12:59 PM GMT

Rontopia

found the Vdrop issue.. not the regulator.. not the Ed Kit.. there was a bunch of R hanging off one the the emulator boards I was using.. all fixed now[noparse]:)[/noparse]

I will write back in a few

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IC layout designer
Austin Texas

Rontopia

ok.. so all is good.. im running the propeller on my handy dandy new regulator.

the problem was I was pulling the leads off the carrier board from a test point that has lots of R.. did not know that at the time so.. I mentioned it to the VP of something around here and he said thats "good feed back" .. course thats what everyone here says when I notice something. so the emulator board that im using should have something silk screened on there that says how much r is hanging off this test point.

all good now.. the propeller is running and the prop plug is running and sending data to the hyper terminal..3.3v and .02A or so is being pulled.

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IC layout designer
Austin Texas

Rontopia

so here are some pics.. not to clear on the second one. its a camera phone with bad light and I had to get really really close.

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IC layout designer
Austin Texas