Communications Mode
CP 523
Figure 7-9. Contents of the Transfer Memory for "Send Message Frame"
Word 6
Data
CPU transfers last message block ( 8 bytes)
CPU transfers further message block (8 bytes each)
CPU issues the "Send message frame" request
End here if CP has not
accepted the Send request!
CPU reads Coordination information
CPU transfers 1st message block (8 bytes)
Word 0
job No.
A001
H
Word 2
Send length
in bytes
Word 4
End-of-text
character
*
Word 6
Not
significant
Word 0
Coordina-
tion
informa-
tion
Word 2
Byte 2: CBS
(coordina-
tion
byte
for
'Send')
**
Word 4
Not
significant
Word 6
Byte 6/byte
7: No. of
subframes/
number of
message
frames
Word 0
Data
Word 2
Data
Word 4
Data
Word 6
Data
CP
- reads job number from
transfer memory
- writes coordination
information into the
transfer memory
CP reads data from the
transfer memory and stores
it in the Send mailbox
CP reads data from the
transfer memory and stores
it in the Send mailbox
CP
- CP
reads
data
from
the
transfer memory and
stores it in the
Send
maibox
- transfers message frames
autonomously
from the
Send mailbox
to
the
peri-
pheral
device
- accepts no Send requests
during this time!
Word 0
Data
Word 2
Data
Word 4
Data
Word 6
Data
Word 2
Data
Word 4
Data
CPU user program
CP functions
Word 0
Data
*
only if Send length = 0 bytes
** relevant only in 3964(R) mode
8-byte
trans-
fer
memo-
ry in
the
CP 523
7-62
EWA 4NEB 811 6044-02a
