SEVERE Bug in mc68360 _ISR_Handler???

Thomas Doerfler Thomas.Doerfler at
Tue Jul 17 14:29:25 UTC 2001

Hi Bob,

> Greetings from the UK.
> I remember there was an interrupt problem with the '360 that we came across
> when we were trying to test the TCP stack about 9 months ago. All I can
> remember is that to fix it, the "tick" timer had to be on the same (or
> lower?) interrupt priority than the network to prevent the very occasional
> scc lockup. At the time Joel and Eric couldn't see what was going wrong -
> and as far as I know it was never tracked down - it was well beyond my
> capability!. I believe there is a comment in a "readme" file enclosed with
> the current 68360 distribution explaining the workaround.
> Am I off track here or could this be the same problem resurfacing?

No you are right, putting the PIT to a lower level also works ok. I 
am really glad to here that I am not the only one who saw that 

I think it is very '360 specific, because all CPM interrupts get 
masked as soon as the CPU has fetched the interrupt vector (oposed to 
many other interrupt sources that remove the interrupt request only 
when the actual peripheral register are accessed).


> Bob Wisdom

IMD Ingenieurbuero fuer Microcomputertechnik
Thomas Doerfler           Herbststrasse 8
D-82178 Puchheim          Germany
email:    Thomas.Doerfler at
PGP public key available at:

More information about the users mailing list