
107
IOWR/IORD Instruction Specifications
Section 6-5
Note
Only one IOWR/IORD instruction (control code #FD00) can be executed dur-
ing a single cycle.
Note
1.
The Equals Flag (SR 25506 for the C200HX/HG/HE) turns ON when pro-
cessing to the ASCII Unit by IOWR/IORD instructions has finished normal-
ly. It remains OFF when processing to the ASCII Unit does not finish
normally. After turning ON, it turns OFF at the execution of the next IOWR/
IORD instruction. Since the Equals Flag will change at the execution of oth-
er instructions/commands as well (such as comparison instructions) be
careful when writing programs.
Normal Completion
Abnormal Completion
2.
The ASCII Busy Flag (IR/CIO n + 5 bit 00) turns ON when the ASCII Unit
is exchanging data with the CPU Unit.
Execution
conditions
n+5 bit
00
ASCII Busy
Flag
Equals Flag
(See note 1.)
IOWR
C
S
D
B
25506
B
A
A
IOWR/IORD instruction
execution
When ON at previous
ladder instruction
Equals Flag
Time
I/O refresh
1
0
Set to allow retry of
IOWR/IORD instruction
IOWR/IORD instruction
execution
When ON at previous
ladder instruction
Equals Flag
Time
I/O refresh
1
0
Содержание C200H-ASC11
Страница 1: ...C200H ASC11 ASC21 ASC31 ASCII Units Operation Manual Revised June 2000...
Страница 2: ...iv...
Страница 4: ...vi...