BU97931FV-LB Datasheet, PDF (12/32 Pages) Rohm – Multifunction LCD Segment Driver

BU97931FV-LB MAX 112 segments (SEG28×COM4)
Datasheet
2. Display control (DISCTL)
MSB
LSB
D/C D6 D5 D4 D3 D2 D1 D0 Hex Reset
1st byte Command
1
0
0
0
0
0
1
0 82h
-
2nd byte Command
0
0
0
0 P3 P2 P1 P0
-
02h
Duty set
Condition
1/4duty (1/3bias)
1/3duty (1/3bias)
Static (1/1bias)
*: Don’t care
P3 P2 Reset state
00
○
01
1
*
In 1/3duty, Display data and Blink data of COM3 are ineffective.
COM1 and COM3 output are same data.
Please be careful in transmitting display data and blink data.
The examples of SEG/COM output waveform, under 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 shown below.
“ OSC frequency = Frame frequency (measurement value) x Divide number ”
Divide number determined 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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26.Feb.2014 Rev.002