Andrew Johnson wrote:
> Kate Feng wrote:
> > For those applications, it seems that the overhead for the
> > VME read/write is necessary to be considered only inside
> > the related ISRs or in the related non-ISR routines where
> > the interrupt has to be disabled, which is rare.
>
> Actually I don't think it's that rare. I have counted something like 30
> calls to the vxWorks intLock() routine in our R3.13.10 support module
> area, most of which are protecting code that manipulates at least one
> card register over the VMEbus while the lock is held.
OK, it's my mistake to add "which is rare".
> In addition I
> counted 79 calls to intConnect(), and most of those ISRs will be
> manipulating VME card registers.
>
> Every one of those drivers must be examined and may have to be modified
> if we decide to use a Tempe-based CPU board here. That's a lot of work!
>
> The PCIbus Retry and Disconnect cycle terminations that you discussed do
> not actually stop the data transfer cycle completely, they only permit
> it to be run again or to take longer to complete than a regular PCIbus
> single I/O cycle.
>
Yes, that's why the overhead is only needed for ISR and where interrupt is
disabled.
It was only a technical statement. It does not imply any project cost
decision
or the amount of work needed.
Kate
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- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Kate Feng
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- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Kate Feng
- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Andrew Johnson
- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Kate Feng
- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Kate Feng
- Re: VME Bus Error handling on MVME3100 and MVME6100 boards Andrew Johnson
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