Technical data
Example
Figures 6-17 and 6-18 illustrate the shifting of information within a
shift register with three pointers and twelve memory cells.
Before the special function is called, certain bits are set in the
pointers (flags) to identify the pointer information, as follows:
Set flag bit 0 of pointer 1 :S F 0.0
Set flag bit 3 of pointer 2 :S F 1.3
Set flag bit 2 of pointer 3 :S F 2.2
The shift register function is then called :JU OB 241
After calling the special function, the 8-bit wide information of the
memory cells is shifted by one cell, as shown below:
Continued on the next page
Pointer 1 Pointer 2 Pointer 3
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
123456 789101112
Flag bit 0
Flag bit 1
Flag bit 2
Flag bit 3
Flag bit 4
Flag bit 5
Flag bit 6
Flag bit 7
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
01
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
1
01
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Fig. 6-17 Schematic showing the principle of a shift register with 3 pointers and 12 memory cells before the
first clock pulse
Pointer 1
Pointer 2 Pointer 3
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
123456 789101112
Flag bit 0
Flag bit 1
Flag bit 2
Flag bit 3
Flag bit 4
Flag bit 5
Flag bit 6
Flag bit 7
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
01
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Fig. 6-18 Schematic showing the principle of a shift register with 3 pointers and 12 memory cells after the
first clock pulse
6
OB 240 to 242: Special Functions for Shift Registers
CPU 928B Programming Guide
C79000-B8576-C898-01
6 - 103