Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 52)

Chapter 4
Ladder-Program Interfaces
4-5
Send VME Interrupt
This message tells the PLC-5/VME processor to assert a VMEbus
interrupt. When the interrupt handler replies with an interrupt-
acknowledge cycle, the status/ID byte is returned to the interrupt handler.
For example:
SVI 2 F0
The example above asserts IRQ2 and gives status/ID value F0H to the
interrupt handler.
Check VME Status File
This message tells the PLC-5/VME processor to check the VME status file
for changes or to update the file with new VMEbus information. Before
executing this command, set bit 8 in element 28 of the VME status file if
you made changes to the file associated with the continuous-copy
configuration and you want the changes to take effect.
This command is needed when the NOCV bit of the status control register
is set.
For example:
CSF
If the NOCV flag in
the VME status/
control register is: This message:
0
serves no useful purpose because the PLC-5/VME processor firmware
periodically checks the VME status file for changes (so that the
PLC-5/VME processor knows to update its internal state to reflect the
changes to the VME status file).
1
allows the ladder program to communicate changes to the PLC-5/VME
processor. An example of such a change would be the ladder program’s
modification of the interrupt mask in the VME status file.
Your ladder program must clear the
Received field for a certain
interrupt level, located in word 24 of
the VME status file, so that the ladder
program can recognize another
interrupt at that level. The update field
in the VME status file must also be set
to one to reflect the fact that the VME
status file has changed and is ready to
receive new interrupt information.
Tip