CP 523
Communications Mode
7.4.2
Reading Coordination Information after "Coordinate Data Transfer"
As soon as the "Coordinate data transfer" request has been transferred to the CP, the CP 523
writes coordination information into bytes 1 to 7 of the transfer memory. This information can be
read out with load operations.
This coordination info is available in Transparent and Interpretive mode after the following
requests:
•
A000
H
:
Read status byte and coordination info
•
A001
H
:
Send message frame
•
A080
H
:
Receive message frame
In ”3964(R) mode”, different coordination info is returned when these same job requests are
issued. This info is discussed at the end of this section.
Table 7-24. Coordination Information after "Coordinate Data Transfer"
* Only after "Receive message" (A080
H
); in the case of an illegal Send request FF00
H
Possible Values
Byte
Meaning
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
0
Status byte
5X
H
1
Permission to send and receive
CPU can neither send nor receive
CPU can send
CPU can receive
CPU can send and receive
00
H
01
H
80
H
81
H
2+3
Message length in bytes
*
0000
H
to 0100
H
4+5
Irrelevant
0000
H
6
Number of message frames
(calculated by the CP after a send request with fixed message
length)
00
H
to 20
H
7
Number of message frames in Receive mailbox
(The CP can buffer up to 100 message frames in the Receive
mailbox. The sum of the length of these messages may not
exceed 1024 bytes. When a message has been entered in the
Receive mailbox, bit 7 of byte 1 is ”0”.)
00
H
to 64
H
Status byte (byte 0)
In the status byte, bits 4 to 7 always have the value 5
H
following a "Coordinate data transfer"
request. Bits 0 to 3 contain error flags.
EWA 4NEB 811 6044-02a
7-47