CP 523
Communications Mode
Figure 7-13. Schematic for "Receive Message"
START
Yes
No
* 5.2
CPU reads transfer memory and evaluates
coordination information and coordination
byte (word 0).
CPU forwards a "Receive message" request to
CP's transfer memory (word 0*)
Is a
message frame in
the Receive mailbox?
(bit 7 in byte 1= 1)
Yes
No
CPU reads message block
from CP's transfer memory
CP transfers data from Receive mailbox
to transfer memory
Read further
message blocks from
transfer memory?
END
CPU writes word 0
EWA 4NEB 811 6044-02a
7-73