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PostPosted: Fri Jan 24, 2014 10:20 am 

Joined: Mon Jan 21, 2013 12:01 pm
Posts: 9
Hi All,

Sry for my english.

If have any person that know hardware, or that know one active good forum hardware of 68000 I need litle help.

I have one project with 68000, and now I will put interrupt. I just used interrupt in another projects and CPU's.

I monitoring the pinouts, FC0-FC2, and when then 68000 receive one interrupt, this pinouts was floating, and not stay in 1 neither 0... Sample: before interrupt, FC0-FC2 stay in 1.5v, 3.5v and 5v. This floating is normal one time the 68000 is executiing many instructions in many modes (supervisor and user)... But when 68000 receive one interrupt (like 000 (nom maskarable), the pinouts FC0-FC2 stay in 2.5v, 2.5v, and 5v. When 68000 responser to one interrupt, he put this 3 pin in 5v (logic 1).

Have any question about instructions or hardware anyone can have ? I tested without replying dtack os vpa, After 5s, he executed any spurioys interrupt and returned to status before interrupt.

Ty a lot for any help
Moacir Jr.

PostPosted: Sun Jan 26, 2014 12:43 am 
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Joined: Thu Dec 16, 2004 6:42 pm
Posts: 1118
I believe FC0, FC1 and FC2 are open collector outputs. (You should verify this!!!) As such they would require a pull-up resistor to VCC.

Prof. Kelly

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