
87
Data Exchange Time Charts
Section 6-4
6-4
Data Exchange Time Charts
6-4-1
PC READ/PC WRITE Timing
After a trigger is sent from the CPU, data is transferred at the next I/O refresh
period. After receiving a PC WRITE or PC READ command, the ASCII Unit
puts the BASIC program on standby until the data transfer is complete.
6-4-2
PC READ@/PC WRITE@ Timing
Data transfer occurs during the I/O refresh period immediately after the exe-
cution of the PC READ@/PC WRITE@ command. The ASCII Unit puts the
BASIC program on standby until the completion of the PC READ@/PC
WRITE@ command.
Write Bit set in ladder diagram
(e.g., using the OUT instruction)
Write Bit
Transfer on PC
READ command *
ASCII Busy
Flag
Write Bit
: I/O refresh
(same below)
* If the number of transfer words
specified in the PC READ command is
more than the max. no. of transfer words
per cycle (set in DM m + 4 bits 08 to 15),
they will be transferred in separate
cycles.
*If the number of transfer words is
completed within one cycle, the ASCII
Busy Flag will not turn ON.
ASCII Unit
CPU Unit
PC READ
RUN
WAIT (Data
transfer standby)
WAIT
(Write Bit standby)
RUN
Transfer on PC
READ@ command*
ASCII
Busy Flag
* If the number of transfer words as specified in the
PC READ@ command is more than the max. no.
of transfer words per cycle (set in DM m + 4 bits 08
to 15), they will be transferred in separate cycles.
ASCII Unit
CPU Unit
PC READ@
command execution
RUN
WAIT (Data
transfer standby)
Summary of Contents for C200H-ASC11
Page 1: ...C200H ASC11 ASC21 ASC31 ASCII Units Operation Manual Revised June 2000...
Page 2: ...iv...
Page 4: ...vi...