Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 68)

Chapter 5
Commands
5-7
This command, whose command word has the value FFFF, sends an
Allen-Bradley Programmable Controller Communications Command. In
the 6008-LTV processor, this was known as the “selective command.”
See Appendix A for a sample implementation of this command.
Figure 5.3
Send-PCCC Command Structure
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Word
Command word
Response word
Cmd interrupt level
Command interrupt status/ID
Reserved
0
1
2
3
4
15
Reserved
Reserved
Width Address modifier
Packet address (high)
Packet address (low)
Packet size
Reserved
6
7
8
9
10
11
Word Command Description
0 Command word Has value FFFFH
1 Response word As defined previously for all commands in common. Note that command completion is defined
th i t h th PLC 5/VME h d th PCCC d d f d
2 Command interrupt level
y
as the point where the PLC-5/VME processor has processed the PCCC command and formed
the reply packet.
3 Command interrupt status/ID
the re ly acket.
7 Width This defines the data width used to perform VME accesses to the packet.
0 denotes D16 and 1 denotes D08(EO).
7 Address modifier This defines the address space in which the packet is accessed.
Only two values are valid: 2D (A16) and 3D (A24 or data falls in PLC-5/VME processor’s
slave memory)
8 - 9 Packet address This specifies the VME address at which the PCCC command packet begins. Bits 23-16 of
the A24 VME address are in bits 7-0 of word 8, and bits 15-0 of the VME address are in
word 9.
If the PLC-5/VME processor’s slave memory is enabled and if this address falls into where
the slave memory is mapped, the data is transferred into the slave memory without performing
any VMEbus accesses. Otherwise, the PLC-5/VME processor does the transfer as a
VMEbus master.
10 Packet size The size of the PCCC command packet in bytes.
Send-PCCC Command