
106
IOWR/IORD Instruction Specifications
Section 6-5
Flags
Note
SR Area addresses for the C200HX/HG/HE, C200H, and C200HS are given
in parentheses.
6-5-3
Using the IOWR and IORD Instructions
1,2,3...
1.
To allow retry processing if data transfer using the IOWR/IORD instructions
fails, be sure to set a self-holding bit in the execution conditions and pro-
gram the Equals Flag (SR 25506 for the C200HX/HG/HE) to release the
bit when the Equals Flag is ON (1).
2.
Program an NC condition for the ASCII Busy Flag (IR/CIO n+5 bit 00) as
an execution condition so that the ASCII Unit does not execute an IOWR/
IORD instruction during data transfer with the CPU Unit.
Value
(see note)
ON
OFF
Instruction
Execution Error
Flag
(ER) (25503)
• The number of transfer words
is not in BCD, or it is 0 words
or is greater than 128 words
• The indirectly addressed DM
address is greater than 6656
or not BCD.
• The destination Unit No. is
outside the range 0 to F, or is
on a SYSMAC BUS Slave
Rack.
• The number of transfer words
is not BCD
C., S., and D. settings are
correct.
Carry Flag
(CY) (25504)
---
---
Greater Than
Flag
(GR) (25505)
---
---
Equals Flag
(EQ) (25506)
Reading was correctly
completed.
Reading was not correctly
completed.
Less Than Flag
(LE) (25507)
---
---
Overflow Flag
(OF) (25404)
---
---
Underflow Flag
(UF) (25405)
---
---
Negative Flag
(N) (25402)
---
---
Содержание C200H-ASC11
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