SM5839A Datasheet, PDF (7/8 Pages) Nippon Precision Circuits Inc – High-Speed Variable-Length Shift Register

SM5839A
FUNCTIONAL DESCRIPTION
Initialization
After power is first applied, up to a maximum of 128
input data cycles are considered invalid. However,
any cycle that momentarily sets the register length to
2 steps (by setting S1 to S6 all LOW) and then to the
desired value is considered to be the first valid cycle.
Resister Length Select
The S0 to S6 inputs set the register length (L) to the
decimal-value given by the following equation using
positive logic (HIGH = 1 and LOW = 0).
L = 64 ⋅ (S6) + 32 ⋅ (S5) + 16 ⋅ (S4) + 8 ⋅ (S3) +
4 ⋅ (S2) + 2 ⋅ (S1) + (S0) + 1
Clock and Output Control
ENRC
×
×
H
L
Input
CLK
×
×
L→H
L→H
Output
Shift register
OE
DOUT0 to DOUT7
L
–
High impedance
H
–
Enabled
×
Circulating
–
× Non-circulating
–
Length
128
127
126
125
↓
66
65
64
↓
3
2
S6 S5 S4 S3 S2 S1 S0
1111111
1111110
1111101
1111100
↓↓↓↓↓↓↓
1000001
1000000
0111111
↓↓↓↓↓↓↓
0000010
000000×
NIPPON PRECISION CIRCUITS—7