Clock not running (was Re: RTEMS4.7 and its tool chain (Re: powerpc mvme5500 clock off by factor of 150))

Peter Dufault dufault at
Tue Mar 8 21:02:41 UTC 2005

On Mar 8, 2005, at 3:39 PM, Till Straumann wrote:

> Hence, you'd have to print the GPP_Interrupt_Cause register contents
> to find the culprit [why the code in irq.c is so complicated is a 
> mystery to me].

The higher level code had derived register "56" as I'd mentioned, which 
traced back to the serial port interrupt.  Printing out the 
ever-pending GPP_Interrupt_Cause is "0x01", which also points to the 
serial port.

I wish there was a way to see that a PPC decrementer interrupt was 
pending, because then I'd just call the decrementer ISR when interrupt 
"56" was called and an interrupt was pending as a proof that this is 
the problem, but I don't see that that is visible in any register.

On the web I see references to errata on the serial port on the 
undocumented interface chip.


Peter Dufault
HD Associates, Inc.

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