Envoy ACP/XF Application Programming Manual

System Procedure Call Specifics for EnvoyACP/XF
EnvoyACP/XF Application Programming Manual–132179
4-21
WRITE[X] Procedure
For WRITE[X] or WRITEREAD[X] requests, the format of the MCW is:
Bit 0 = 0: Do NOT set P/F bit.
= 1: Set P/F bit.
Bit 1 = 0: The frame is a numbered I-frame. Return completion when the
remote station acknowledges a successful receipt.
= 1: The frame is a command/response U-frame. Return a completion
immediately.
Bit 2 = 0: The information field is present in this command/response U-
frame.
Note. Do not set bit 2 to 1 even if there is no data to transmit; EnvoyACP/XF requires that the
information field be present even if it is empty.
Bits 3-7 = Value specifies a command/response code for a U-frame. This
value causes EnvoyACP/XF to place the appropriate
command/response code into bits 0, 1, 2, 4, and 5 of the control
field of the U-frame. See Table 4-5.
Bits 8-15 = For point-to-point applications, the content of bits 8 through 15
must be set to 0.
For multipoint applications, the content of bits 8 through 15 must
contain a station index referring to a tributary station entry in the
DEFINELIST station list. In a supervisor application, bits 8
through 15 identify the tributary to which the frame is targeted. In
a multi-address tributary application, bits 8 through 15 identify
the address of the particular tributary station that is sending the
frame.
Table 4-5. MCW Values for U-Frame Command/Response Codes (page 1 of 2)
MCW.<3:7>
Decimal Value
MCW.<3:7>
Octal Value
U-Frame
Command U-Frame Response
0 %00 UI UI
2 %02 nonreserved 0 nonreserved 0
4%04UP
10 %12 nonreserved 1 nonreserved 1
12 %14 UA
18 %22 nonreserved 2 nonreserved 2
23 %27 XID XID
25 %31 CFGR