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

Peter Dufault dufault at
Wed Mar 9 01:09:41 UTC 2005

On Mar 8, 2005, at 6:44 PM, Till Straumann wrote:

> You can try a busy loop to check if the decrementer is running at all.
> From your main/init task call

Huh, it's running all right, but the values I'm seeing are odd.  I put 
it in a loop and got the value 10 times, and I'm seeing:

Decr rollover -- initial value was 0x3fe18d88, msr is 0000b032

and so on, with the value displayed varying from 0x3fbbb6611 to 
0x4dff9215.  And they aren't descending, and they don't come out at 
once it takes a while.

But I thought that assembler in c_clock.c, which I can't read, was 
reloading the counter with

asm volatile ("mfdec %0; add %0, %0, %1; mtdec 

so if the interrupt went off and it reloaded I expect the value printed 
in the test code you gave me to be under the 333330 that corresponds to 
10ms, right?

So interrupts are enabled (we can see that from the MSR), the board 
TBEN is asserted (I checked, and it powers up that way), The processor 
TBEN is enabled in HID0 (I've checked many times), the decrementer is 
running (we see that above), but the reload doesn't seem to be 
happening because the interrupt isn't triggering.


Peter Dufault
HD Associates, Inc.

More information about the users mailing list