7: BASIC INSTRUCTIONS
USER’S MANUAL 7-25
Reverse Shift Register (SFRN)
For reverse shifting, use the SFR instruction followed by the NOT instruction. When SFRN instructions are programmed,
two addresses are always required. The SFR and NOT instructions are keyed, followed by a shift register number selected
from appropriate operand numbers. The shift register number corresponds to the lowest bit number in a string. The number
of bits is the second required address after the SFR NOT instructions.
The SFRN instruction requires three inputs. The reverse shift register circuit must be programmed in the following order:
reset input, pulse input, data input, and the SFR and NOT instructions, followed by two required addresses.
I1
I0
Ladder Diagram
Key Operation
LOD
10
SET
I
Prgm Adrs Instruction Data
0
1
2
3
5
6
7
8
9
10
11
LOD
LOD
LOD
SFR NOT
OUT
LOD
OUT
LOD
OUT
LOD
OUT
I0
I1
I2
20
7
Q0
R21
Q1
R23
Q2
R25
Q3
Program List
R20
N7
1
BPS
0
Reset
Pulse
LOD
10
SET
I
LOD
10
2
BRD
I2
Data
LOD
10
SET
I
SFR
R
R21
R23
R25
OUT
16
RST
F
Q
0
LOD
10
SFR
R
OUT
16
RST
F
Q
LOD
10
SFR
R
OUT
16
RST
F
Q
LOD
10
SFR
R
OUT
16
RST
F
Q
1
BPS
1
BPS
2
BRD
2
BRD
3
BPP
Q1
Q2
Q3
Q0
Last Bit:
0 to 63 (standard processing mode)
0 to 31 (high-speed processing mode)
# of Bits:
1 to 64 (standard processing mode)
1 to 32 (high-speed processing mode)
NOT
A
2
BRD
0
7
END
2
BRD
3
BPP
2
BRD
5
CC=
Structural Diagram
I2
I0
R20
Reset
Data
I1
Pulse
R21 R22 R23
Shift Direction
Last Bit: 20 # of Bits: 7
R24 R25 R26
Note: Output is initiated only for those bits highlighted in bold print.
Note: When power is turned off, the statuses of all shift register bits are normally cleared. It is also possible to maintain
the statuses of shift register bits by setting FUN4 as required. See page 5-5.
• The last bit status output can
be programmed directly
after the SFRN instruction
with two required addresses
is keyed. In this example,
the status of bit R20 is read
to output Q0.
• Each bit can be loaded using
the LOD SFR R# instruc-
tions.
• For details of reset, pulse,
Note: To enter a decimal constant as the
number of bits, press the LOD/10 key
followed by the number of bits.
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