Omron C200H-ASC11, Manual, Page: 98 / 301

89
Data Exchange Time Charts
Section 6-4
6-4-6 IOWR (#FD00)/IORD (#FD00) and PC QREAD/PC QWRITE Timing
Data transfer occurs as soon as a trigger arrives from the ASCII Unit and the
IOWR (#FD00)/IORD (#FD00) command is executed. The ASCII Unit is on
standby from the execution of the PC QREAD/PC QWRITE command until
the execution of the IOWR (#FD00)/IORD (#FD00) command.
6-4-7 Combined IOWR (#00
@@
), IOWR (#CC00), ON PC GOSUB, and PC
EGET Timing
Data is transferred immediately by the IOWR (#00
@@
) instruction. The IOWR
(#CC00) instruction sends an interrupt to the ASCII Unit. The ASCII Unit
receives data via the PC EGET command in an interrupt subroutine. Data
transfer in the CPU Unit is completed within 1 cycle.
ASCII Busy
Flag
IOWR Request
Flag
ASCII Unit
CPU Unit
PC QREAD
RUN RUN
IOWR (#FD00)
instruction execution
IOWR Request
Data transfer by the
IOWR instruction
Note The ASCII Busy Flag turns ON for PC QREAD only.
It does not turn ON for PC QWRITE.
WAIT
U ASCII Unit
CPU Unit
ON PC
GOSUB
R N
IOWR (#00
@@
)
Transfer by the
IOWR instruction
Subrou-
tine
branch
IOWR (#CC00)
PC EGET