
2.4 Instruction Details
1
2
3-141
Chapter 2 Instructions
Arithmetic flag
2009 No change
2010 Turns ON when the contents of the internal register is "0" after
"LDA #00000" is executed. Turns OFF at other times.
2011 No change
2012 Turns ON when the DM or relay indirectly addressed with #TM is
out of range.
➮
"Indirect addressing" (p. 3-127)
Application of LDA and STA instructions
■ Changing the counter setting value
Coding
Description
• In step
a), contents of DM00100 is transferred to C001 via the internal register for
use as the C001 preset value, when 0000 is ON.
• In step b) , contents of #00200 is transferred to C001 via the internal register for
use as the C001 preset value, when 0002 is OFF.
• Although the C001 preset value is #09999 in the above example, any value
except #00000 can be given because the preset value is changed to the speci-
fied value by turning ON/OFF 0000.
Note 1: If an STA instruction is executed when the current value is larger than the
preset value, the current value will be changed to the preset value.
Note 2: Do not specify "#00000" as the setting value for C001.
When 0000 is ON, #00100 is transferred as C001
preset value.
When 0000 is OFF, #00200 is transferred as C001
preset value.
When C001 current value equals to its preset value,
0500 turns ON.
0000
C001 0500
b)
#00100
LDA
C001
STA
0000
0002
#00200
LDA
C001
STA
#09999
C001
0001
a)
Line No. Instruction Operand
0000 LD 0000
0001 LDA #00100
0002 CON
0003 STA C001
0004 LDB 0000
0005 LDA #00200
0006 CON
0007 STA C001
0008 LD 0002
0009 C 001 #09999 0001
0010 CON
0011 AND C001
0012 OUT 0500
LDA / @LDA / STA @STA
KVNKA Chap 02_4cP.p65 08.3.11, 0:02 PM141
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