Disconnected Prop Plug causing resets...

ght_dak

Got the Propeller DIP Plus Kit working with the Prop Plug... but I notice that when I disconnect the USB·link between the Plug·and the computer, the Plug causes periodic (every few seconds) resets.· Tried pulling the reset line high with a 10K resistor (guess???) but to no avail.

So, I'm yanking the prop plug from the breadboard instead of just disconnecting the USB cable... all works fine then.

The Plug doesn't get power from the board... so must get it from the USB source.· Hmmm....· Is one supposed to disconnect the entire plug instead of the USB connection?· Seems unlikely...

The Plug has no other problems from what I can tell.

Do I simply have a bad Plug? (beginning to seem that way...)
·

Phil Pilgrim (PhiPi)

See my postings in this thread: http://forums.parallax.com/showthread.php?p=651731. The problem you are experiencing is likely a consequence of the USB chip being intermittently powered from the Propeller through one if its I/O pins. A workaround that seems to have succeeded for the PropSTICK-USB may work for you, too.

-Phil

ght_dak

Yup, that fixed it. 1K pullup on P30 and no more resets from the Plug.

So we see this with Prop Plugs and PropSTICK-USBs... I imagine there might be quite a few folks out there experiencing this problem.

Thanks Phil.

-glenn

Fred Hawkins

Phil Pilgrim (PhiPi) said...
The problem you are experiencing is likely a consequence of the USB chip being intermittently powered from the Propeller through one if its I/O pins.

What about the opposite case -- the USB plug powering the prop's circuits? When I have the plug connected and no other power applied to my
PropEd board, the power on led glows dimly.

Phil Pilgrim (PhiPi)

Yes, that can happen: the Prop and anything else connected to Vdd will be powered through the "high" on pin 31. This situation should probably be avoided, due to the potential load it presents to the USB chip's output pin, as well as to the input protection diode in the Propeller.

-Phil