avr hangs when i turn pc off

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

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rb76543
 
Posts: 29
Joined: Sat Dec 15, 2007 7:52 pm

avr hangs when i turn pc off

Post by rb76543 »

my pc somehow pulls the reset low when i turn it off, which sucks, because i have to unplug the usb connector for my avr to continue operating. since my avr controls a system 24/7/365, it has to keep running whether or not my pc is on

http://farm3.static.flickr.com/2112/215 ... 25c8_o.jpg

so, i did this: cut the trace that shorts the obsolete jumper called 'bus pwr' (located close to the usb connector), then put the jumper on 'usb pwr', which means that now my avr power source is driving both chips on the usbtinyisp board.

no more resets from my un-powered pc. yay!

usbtinyisp & avrdude source == total coolness.

later,

rod

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »

one thing you may want to try is put a stronger pullup (like, say 4.7K) on the avr pullup line. why do you have the usbtiny attached if its not programming it? :?

rb76543
 
Posts: 29
Joined: Sat Dec 15, 2007 7:52 pm

Post by rb76543 »

ladyada wrote: why do you have the usbtiny attached if its not programming it? :?
general spi communication. my avr controls a system, and my client likes to see the status on his pc. so, i have a program that monitors the avr, via your usbtinyisp. but, he turns his pc off when he goes home. when he comes back to work the next day, he wants to see what happened overnight.

if the avr was hung all night, he is confused.

if he has to pull the connector each night when he leaves, well, that's a lot to ask of him

if none of this makes sense to you, i appologize. i'm not good at explaining things.

thanks,

bye

rod

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