PST with USB cable unplugged

Roger Lee · 2010-05-10 04:25

Running a program using "Parallax Serial Terminal" for debug.
It hangs up without the USB plugged in. Resets continuously.

Q: Can the spin code for "Parallax Serial Terminal" be left in somehow?

Q: Do I have to comment all these lines for it to run unplugged?

Cluso99 · 2010-05-10 04:29

This has been discussed many times on the forum. When the USB is unplugged and the FTDI chip is on the pcb, the prop powers the FTDI chip through the output pin causing continual resets. Disable the PST for FDX driver in your code and all should be fine.

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Roger Lee · 2010-05-10 14:11

egad, What a can of worms!

My code has now has about 130 search-able comments added.

Cluso99 · 2010-05-11 01:54

It is a know problem with the FTDI chip.

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Links to other interesting threads:

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· 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

Phil Pilgrim (PhiPi) · 2010-05-11 02:35

It's not a problem with the FTDI chip. It's a problem with the way it's implemented.

-Phil

Roger Lee · 2010-05-11 03:02

ouch! Touchy subject.

Really I'm OK for now. It's just such a pain in the rear.

Perhaps I'll hear more about this issue on Saturday.

Not going to ruin my weekend.

Have at it, I'm getting out of the way.

Phil Pilgrim (PhiPi) · 2010-05-11 03:55

Roger,

'Sorry for the implied exasperation. It's just that this has been a long-standing hardware design issue which, despite having a simple solution costing pennies, has yet to be addressed.

In the meantime, if you pull A30 and A31 up to Vdd with 4.7K resistors, your problem will disappear. This will provide enough power to the FTDI chip, without the USB cable connected, to keep it from toggling DTR, which is the source of your present difficulties. It's kludgy, but it works.

-Phil

Oldbitcollector (Jeff) · 2010-05-11 13:13

Roger Lee said...
egad, What a can of worms!

My code has now has about 130 search-able comments added.

Would a PST dummy object be helpful? Something that you could simply "remark" in/out in the OBJ section?
Attached is a "dummy" which should make it so that you only edit 1 line of code, instead of 130.

OBC

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SRLM · 2010-05-11 13:42

Thanks OBC! I like your solution to the problem.

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Roger Lee · 2010-05-11 15:50

Phil, Thanks so much.

OBC, good idea - could work!

PST Dummy is not a drop in replacement,yet.
Don't know if you intended for it to be.
Were you just showing me the concept

I'm using the constants that are now undefined (pst#NL).

edited my code last night to add (and again today)

OBJ           

'{'
  pst   :       "Parallax Serial Terminal"
'}'

PUB init      ' starts pst

'{'
    pst.start(115200)
    pst.home
'}'
    
  main

can now use find/replace twice to change all.
also edited out half of the PST calls.

Roger

Post Edited (Roger Lee) : 5/11/2010 4:20:38 PM GMT

John R. · 2010-05-11 20:54

Oldbitcollector said...

Would a PST dummy object be helpful? Something that you could simply "remark" in/out in the OBJ section?
Attached is a "dummy" which should make it so that you only edit 1 line of code, instead of 130.

OBC

You mean kind of like a #IFDEFINE statement?· (he said grinning at another sore point...)

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John R.
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Oldbitcollector (Jeff) · 2010-05-12 00:02

Roger Lee said...
Phil, Thanks so much.

OBC, good idea - could work!

PST Dummy is not a drop in replacement,yet.
Don't know if you intended for it to be.
Were you just showing me the concept

I didn't test it, but it should work fine as a drop in..

OBC

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max72 · 2010-05-18 12:29

I cannot test it now, but if I remember correctly it is enough to comment the start call. One line of code is not too bad..

BradC · 2010-05-18 13:14

max72 said...
I cannot test it now, but if I remember correctly it is enough to comment the start call. One line of code is not too bad..

I'd have thought if you failed to start the object then eventually the transmit buffer would fill up and your program will hang on a tx call.

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Phil Pilgrim (PhiPi) · 2010-05-18 15:11

BradC said...
I'd have thought if you failed to start the object then eventually the transmit buffer would fill up and your program will hang on a tx call.

A well-written object would not allow that to happen. If the actions of an object's method are anything other than benign, the method should check first to see if the necessary cog(s) have been started before proceeding and, if not, simply return without doing anything.

-Phil

max72 · 2010-05-18 15:30

I did a rapid test right now, and commenting the start method is not working.

A dummy object in fact requires to modify only one line. I'll use this solution. Thanks.

Massimo

Oldbitcollector (Jeff) · 2010-05-18 16:38

I suspect the "dummy" object will need a "little" code placed back into it. (VAR's I think) but
should be the next best thing to fixing the hardware issue which is plaguing us.

OBC

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max72 · 2010-05-18 20:25

I tested the dummy just changing the object name in my test spin, and it worked out of the box.

PST with USB cable unplugged

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