Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 44)

Chapter 3
VMEbus Interface
3-6
Offset Register
1 1 1 1 1 1 1 1 SLAVE BASE
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
07
offset
The SLAVE-BASE field in the offset register defines the A24
mapping of the PLC-5/VME processor; register bits 15-8 are the values of
the VME address bits A23-A16. This field is not altered by the
PLC-5/VME processor.
Command Control Register
WRDY LOCK ERR 1 COPY-TO-STATE COPY-FR-STATE ERROR CODE
Command Control and Lock Register
WRDY LOCK ERR 1 COPY-TO-STATE COPY-FR-STATE ERROR CODE
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
09
offset
0B
The command-control register and command-control-and-lock register
contain state bits (Table 3.B) associated with the command register. They
are identical except how they read the command-control-and-lock register
and affect the state of the LOCK bit. The command-control-and-lock
register and the LOCK bit are provided to support multiple independent
senders of commands to the PLC-5/VME processor; you can ignore both
the register and the bit if you do not need this facility.
Table 3.B
Registers Containing State Bits
Bit Register Function Definition
15 WRDY Write ready If 1, the command register is armed for an incoming command.
A write to the command-low register clears this bit.
14 LOCK Command register lock If 1, the command register has been locked.
If clear, the command register can be locked for the sending of a command.
13 ERR Protocol error If 1, a protocol error occurred associated with the last command received.
11-10 COPY-TO-STATE The current state of the
continuous-copy-to-VME
operation 00 None is enabled
01 Currently enabled and no errors encountered
10 Currently enabled but a noncatastrophic error has occurred
11 Shutdown because a catastrophic error has occurred
9-8 COPY-FROM-STATE The current state of the
continuous-copy-from-
VME operation
Same encoding as above.
7-0 ERROR CODE Error code If ERR=1, this field is a code describing the error.
See specific requesting command types or Appendix D for a list of error codes.