BU97981KV-E2 Datasheet, PDF (22/50 Pages) Rohm – Multi-function LCD Segment Drivers

BU97981xxx Series MAX 196 segments (SEG49xCOM4)
Datasheet
Display Control (DISCTL)
1^st byte Command
2^nd byte Command
MSB
LSB
D/C D6 D5 D4 D3 D2 D1 D0 Hex
1
0 0 0 0 0 1 0 82h
0
0 0 0 P3 P2 P1 P0
-
Reset
-
02h
Duty Set
Condition
1/4duty (1/3bias)
1/3duty (1/3bias)
Static (1/1bias)
*: Don‟t care
P3 P2 Reset state
0
0
○
0
1
1
*
In 1/3duty, Display data and Blink data of COM3 is ineffective.
COM1 and COM3 output are same data.
Please be careful of transmission of display data and blink data.
The examples of SEG/COM output waveform, under the each Bias/Duty set up, are shown at “LCD Driver
Bias/Duty Circuit” description.
Frame Frequency Set
Condition
(1/4,1/3,1/1duty)
P1
P0
(128Hz, 130Hz, 128Hz)
0
0
(85Hz, 86hz, 64Hz)
0
1
(64Hz, 65Hz, 48Hz)
1
0
(51Hz, 52Hz, 32Hz)
1
1
Reset state
○
Relation table, between Frame frequencies (FR), integrated oscillator circuit (OSC) and Divide number.
Divide
FR [Hz] ^(Note1)
DISCTL
(P1,P0)
Duty set (P3,P2)
(0,0)
1/4duty
(0,1)
1/3duty
(1,*)
1/1duty
Duty set (P3,P2)
(0,0)
1/4duty
(0,1)
1/3duty
(1,*)
1/1duty
(0,0)
160
156
160
128
131.3
128
(0,1)
240
237
320
85.3
86.4
64
(1,0)
320
315
428
64
65
47.9
(1,1)
400
393
640
51.2
52.1
32
(Note1) FR is frame frequency, in case OSC frequency = 20.48KHz (typ).
The Formula, to calculate OSC frequency from Frame frequency is below.
“ OSC frequency = Frame frequency (measurement value) x Divide number ”
Divide number：Please decide by using the value of Frame Frequency Set (P1,P0) and duty setting (P3,P2).
Ex) (P1,P0) = (0,1) , (P3,P2) = (0,1) => Divide number= 237
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10.Apr.2015 Rev.006