Chapter 3 Software Overview
NI-VXI User Manual
3-64
© National Instruments Corporation
specification requires that all VXI Commanders monitor the PASSed or
FAILed state of their VXI Servants. When a VXIbus device is in the
FAILed state, the failed device clears its PASS bit (in its Status
register) and asserts the SYSFAIL* signal on the VXIbus backplane.
When a Sysfail condition is detected on the local CPU, an interrupt is
generated, and the current Sysfail interrupt handler is called. The failed
Servant device must be forced offline or brought back online in an
orderly fashion.
EnableSysreset (controller)
EnableSysreset
sensitizes the application to Sysreset interrupts from
embedded or extended controller(s) (dependent on the hardware
platform). Notice that if the local CPU is configured to be reset by
Sysreset conditions on the backplane, the interrupt handler will not get
invoked (the CPU will reboot).
GetACfailHandler ()
GetACfailHandler
returns the address of the current ACfail interrupt
handler. An ACfail condition detected on the local CPU generates
an interrupt that calls the current ACfail interrupt handler. Your
application can take any appropriate action within the allotted time
period before complete power failure. The
InitVXIlibrary
function
automatically installs a default handler,
DefaultACfailHandler
,
when it initializes the NI-VXI software.
GetBusErrorHandler ()
GetBusErrorHandler
returns the address of the current bus error
interrupt handler. During an access to the VXI/VMEbus, the BERR*
signal (bus error) is asserted to end the bus cycle if the address or mode
of access is determined to be invalid. The bus error exception condition
generates an exception on the local CPU, which can be trapped by the
bus error handler. Your application should include a retry mechanism if
it is possible for a particular access to generate bus errors at times
and valid results at other times. The
InitVXIlibrary
function
automatically installs a default handler,
DefaultBusErrorHandler
,
when it initializes the NI-VXI software. It increments the global
variable
BusErrorRecv
. Because bus errors can occur at any time, a
corresponding enable and disable function is not possible.
