75
Details of the Data Exchange Methods
Section 6-3
Comparison Chart of Data
Exchange Methods
The differences between the data exchange methods are shown in the table
below.
Note
There are some restrictions in the memory area addresses that can be used
for methods 1 and 2. Refer to
6-6 Restrictions for CS1-series PCs
for details.
Use methods 3 to 8 whenever possible.
6-3
Details of the Data Exchange Methods
6-3-1
Data Exchange Method No. 1
The ASCII Unit reads/writes the CPU Unit memory during the I/O refresh
period on a trigger from the CPU Unit.
This method allows the exchange of comparatively large volumes of data with
a maximum of 255 words, although it will cause the ASCII Unit to be on
standby for some time. It is possible with any CPU Unit.
Data ex-
change
method
CPU Unit
instructions
ASCII Unit
commands
Acces-
sing
Unit
Access
trigger
Transfer
timing
ASCII
program
Max. no. of transfer words
Per
command
Per cycle
1
MOV etc.
(specify
memory
read/write area
for
execution of
PC WRITE/PC
READ
commands)
PC WRITE
PC READ
(Reads/writes
the CPU Unit’s
I/O memory)
ASCII
Unit
CPU
Unit
At I/O refresh
Pauses at
execution of
PC WRITE/
PC READ until
completion of
transfer.
PC WRITE/
PC READ: 255
words
Using a
C200HX/HG/
HE or
CS1-series PC,
and when the
number of bytes
transferred per
cycle set in the
Setup Area (Bits
08 to 15 of DM
m + 4) is 5A:
127words
00: 20words
2
Programming
not required
PC WRITE@
PC READ@
(Reads/writes
CPU Unit
memory)
ASCII
Unit
ASCII
Unit
At I/O refresh
Pauses at
execution of
PC WRITE@/
PC READ@,
until completion
of transfer.
PC WRITE@/
PC READ@:
255 words
3
MOV, LD, etc.
PC GET
PC PUT
(Reads/writes
allocated
IR/CIO area
words)
Either
Either
At I/O refresh
Execution does
not stop.
PC PUT: 1word
PC GET:
2words
PC PUT: 1word
PC GET:
2words
4, 5
IOWR
(#00
@@
)
IORD (#00
@@
)
(C200HX/HG/
HE or
CS1-series PC
only)
PC EGET
PC EPUT
(Reads/writes
to ASCII Unit’s
shared
memory)
CPU
Unit
Either
At IOWR/IORD
(#00
@@
)
execution
Execution does
not stop.
PC EGET/
PC EPUT:
90words
IOWR/IORD
(#00
@@
): 90
words
No restrictions
6
IOWR (#FD00)
IORD (#FD00)
(C200HX/HG/
HE or
CS1-series PC
only)
PC QREAD@
PC QWRITE@
CPU
Unit
ASCII
Unit
At IOWR/IORD
(#FD00)
execution
Pauses at
execution of
PC QREAD/
PC QWRITE
until IOWR/
IORD (#FD00)
has been
executed.
PC QREAD/
PC QWRITE:
128 words
IOWR, IORD
(#FD00):
128words
No restrictions
7, 8
IOWR
(#00
@@
)
IORD (#00
@@
)
+ IOWR
(#CC00)
(C200HX/HG/
HE or
CS1-series PC
only)
ON PC
GOSUB
PC EGET/
EPUT
CPU
Unit
CPU
Unit
At IOWR/IORD
execution
Execution does
not stop.
No restrictions
Summary of Contents for C200H-ASC11
Page 1: ...C200H ASC11 ASC21 ASC31 ASCII Units Operation Manual Revised June 2000...
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