Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Wed, 24 Jul 2002 09:42:06 -0600

Be careful that all pointers to device registers are declared
"volatile". 

Also, make certain that your vxWorks BSP is configuring the MMU to turn
off caching for device address spaces. I assume that this is handled by
your BSP for A16, but if the device has additional registers in A24 or
A32 then you may need to make system calls in the device driver to
properly map the device addresses in the MMU.

Jeff

> -----Original Message-----
> From: ahed aladwan [mailto:[email protected]]
> Sent: Wednesday, July 24, 2002 7:58 AM
> To: Leng, Yongbin; tech-talk
> Subject: Re: ISEG VHQ204L Driver
> 
> Hi All,
> 
> I got the driver from kristi luchini in SLAC,  ftp.slac.stanford.edu
> 
> But I have another preoblems with the ISEQ VHQ202 VME module:
> 
> When the master (PPC MVME2304, vxWork 5.3.1) reads the data from the
> slave (A16, D16, address mod is 0x2D or 0x29), it seems that for some
> addresses the master get the data for the next address (+ 1 byte),
using
> a logic analyzer to check the master read cycle (attached pdf file), I
> have noticed that because the master apply address pipelining
> (forcasting) and the slave dosen't latch the data (or address), I got
> wrong data.
> But what I can't understand why this happens only for some addresses
but
> not all, espicialy the base address (status register) (ISEQ has no
clue)
> Is it a bad design of the slave or there is something unclear for me
in
> the master configuration, what is the situation with other labs who
uses
> similar card model and different IOC, moreover according to Tundra
> (universe chip, PCI - VME bridge) it is not possible to disable
address
> pipelining.
> 
> I appreciate any suggestions.
> 
> Best regards,
> Ahed Aladwan
> 
> 
> Leng, Yongbin wrote:
> 
> >Hi Guys,
> >
> >SNS diagnostic controls is planing to use ISEG VHQ204L in BLM system.
> >And someone told me its EPICS driver is available. But I can't find
it
> on
> >EPICS homepage.
> >Does anyone have EPICS driver for VHQ204L and can shared it with us?
> >
> >Thanks in advance.
> >
> >Yongbin Leng
> >631-344-2835
> >SNS controls, BNL
> >UPTON, NY 11973
> >
> >
> 
> --
> ====  Ahed AlAdwan, WSLA/208, Swiss Light Source / Paul Scherrer
> Institut, CH-5232 Villigen
> ====  phone: +41-56-3104594  fax: +41-56-3104413
> ====  mailto:[email protected]    http://www.psi.ch
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System