Experimental Physics and
Industrial Control System

Kate Feng <[email protected]> · Fri, 26 Mar 2004 13:38:38 -0500

Kate Feng wrote:

> I agree with you  that one should enable the posted write by default.
> However, it could be disabled, which means the address
> pipelining on the  UniverseII could be disabled as well on the Mvme5500.
> I thought the origianl issue is "to disable the  address pipelinig".
> It  looks like you have a reason to disable the posted write
> for the NI VME-MXI-1.   The trad off is to sacrifice the bandwidth
> of the VME bus.  However, I do not know if  the decrease is
> significant for your application.   I hope this helps.
>

I  ran a   short test, which  showed  a decrease of  33% in
performance for the posted-write disabled mode.  It might not be worse
than the VMEchip2 that was used on the MVME167, which is in
your existing system.   I do not have  the datasheet for the
VMEchip2.  I guess it does not provide address pipeling,
which explained why it worked fine with the  MXI-1.

Again,  hoping this helps.   -- Kate

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System