Propeller Reset Problem

Community General Discussions
1

 

(This is a double-post and is over at the prop forums as well --that is why it is written funny)

I am running a Gadget Gangster USB prop board on Walter, my robot. Walter is about as big as a dog, weighs about 80 lbs and is super awesome. The major parts (that would have any bearing to this conversation) are the main board, a Arduino-based motor driver board speaking i2c, a second arduino that simply fires off my (4) sonars and sends the data to the prop (UART serial), a thumb-drive mp3 player (speaking serial) and a i2c servo driver board. The 5V regulator (on the prop board itself) has been jumped (per manufacturer's instructions) and 5v power is supplied by an external 5v 3A regulator. Everything else --main drive and servos have their own volt regulators. Juice comes from a big ol' 12V SLA battery. There is more --blinkM's etc. but nothing else worth mentioning.

I am having problems with the chip/board doing it's own "hard reset". This is a new problem, and did not exist in the past using the same hardware and similar code. When I say "hard reset" I mean that the main 5V power supply is being pulled low. I even caught it on a scope. This is a picture of the reset. When this was taken, I had the probe on the main 5V supply (from the 5v regulator and the same supply that feeds everything 5v) and the ground.

Scope_of_Prop_reset.jpg



You can see that “something” is yanking my power down to nothing. It is the same swoop down to low then a square corner and it shoots back to high. The O-scope says that every reset is exactly the same length give or take a few uS. If you have turned the board on for the first time, the reset happens after about 4 minutes. If you let it run from there, the resets come more frequently --sometimes every 15 or 20 seconds. They resets seem to also happen more when more cogs are running. Removing the WiiCamera object and code seems to help but I can’t confirm that removing it fixes my problem. I would have thought this was an “overflow” or a “null-style” problem (it feels like that kinda problem), but I don’t like the looks of the scope trace --This is not just some kinda internal reset from code that blew-up, something is pulling down hard.

Here is the code I am running. I did a tidy-up and a bunch of comments.
(Don’t click the big button when you get there–it is an ad)
Look for “Navigation 20 --Reset Problem”
Code is Here

I thank you all in advance for your time.

2

I have no physical experience, but …

I have read about PICs and there is a Brown Out Reset fuse that can be set or not. Is it possible there is a similar fuse in a prop?

3

Two Thoughts

Hi Chris,

I’m wondering on -

a) Thermal cut out on the 5v reg - maybe running border line? Would sort of sit with the initial 4minutes and then  more frequent happening.  Have you put an ammeter on the 5v bus and checked the actual current draw ( and temp) and do you have a suitable heatsink on the reg.

b)  What about the total current draw on the prop - you may be OK for each I/O individually but there is usually a max rating overall as well

I bow to your superior build skills and knowledge but I have had the thermal problem which was a swine to track down