Objective Development Forums 2012-02-02T11:05:38+02:00 https://forums.obdev.at/app.php/feed/topic/6411 2012-02-02T11:05:38+02:00 2012-02-02T11:05:38+02:00 https://forums.obdev.at/viewtopic.php?t=6411&p=20849#p20849 <![CDATA[Re: usb got disconnected as pin attached with PC Fan speed wire]]> Statistics: Posted by fkpwolf — Thu Feb 02, 2012 11:05 am

]]> 2012-01-30T16:10:15+02:00 2012-01-30T16:10:15+02:00 https://forums.obdev.at/viewtopic.php?t=6411&p=20825#p20825 <![CDATA[usb got disconnected as pin attached with PC Fan speed wire]]>
It works well at most test case. And now I want to use it to monitor common 4pin PC Fan speed. I use Timer 0 overflow interrupt:

Code: 

TCCR0B = 0x02;// 1:8 presc. 
TCNT0 =0;
TIMSK= 1 << TOIE0; //unmark Timer 0 overflow interrupt
.......
ISR(TIM0_OVF_vect) {......

It is simple. But when fan's speed wire was connected any pin of pb5/pb3/pb0 and then turn on the fan, usb got disconnected. I also tried pin change interrupt, and got same result. Only when I used pb4, usb works steady but input data was always 0.

I curiosity that why only pb4 was working?

Statistics: Posted by fkpwolf — Mon Jan 30, 2012 4:10 pm

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