Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Tue, 30 Nov 2021 08:09:11 -0800

On 11/30/21 7:05 AM, Johnson, Andrew N. wrote:
> On Nov 29, 2021, at 8:33 PM, Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov <mailto:tech-talk at aps.anl.gov>> wrote:
>>
>> On 11/28/21 9:12 PM, Peter Linardakis via Tech-talk wrote:
>>> vmeTsi148 IRQ manager: looking for registers on VME...
>>> Trying to find CSR on VME...
>>> *********
>>>
>>> Does anyone have any ideas why a certain backplane will cause this?
>>
>> CSR in this context refers to the CSR address space, which
>> is a VME64 extension using the geographic address pins,
>> which won't be present in an older VME32 crate.
>>
>> Still, this error shouldn't be fatal as the TSI148 driver
>> should fall back and print "Trying to find CRG on VME...".
>>
>> https://github.com/RTEMS/rtems/blob/e945e3fc4d6a6a74789c9a348120ec7d06e19231/bsps/powerpc/shared/vme/vmeTsi148.c#L1715 <https://github.com/RTEMS/rtems/blob/e945e3fc4d6a6a74789c9a348120ec7d06e19231/bsps/powerpc/shared/vme/vmeTsi148.c#L1715>
> 
> Since the CPU on this backplane apparently hangs before printing that “CRG” message, my guess is that either the VME system controller isn’t generating a BERR signal if/when nothing responds to the I/O cycle after some suitable timeout interval (I assume from the probe operation in the call at line 1717), or maybe that the backplane has a problem with its BERR* signal line not working properly (is it terminated properly?). If the CPU doesn’t see a falling edge on either the BERR or DTACK signal it will hang waiting for a data from the read cycle which never completes. If this CPU *is* the VME system controller the code should have enabled a cycle timeout, but going back to what Heinz was talking about you need to make sure that the SCON is properly enabled and that the CPU is in slot 0.

For what little it is worth, I once successfully setup a mvme3100
with RTEMS (4.9.x) in an old (antique?) VME32 crate.  However,
that was 10 years ago and I don't now recall what all I had to do.

wrt. SCON there are a pair of DIP switches in the S4 bank which can
be set to force a mvme3100 to be SCON.

see sections 1.4.2 and 1.4.3.

https://www.slac.stanford.edu/grp/lcls/controls/global/hw/users_guides/vme/cpu/mvme3100/MVME3100-programmer-ref.pdf

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System