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

BU97931FV MAX 112 segments (SEG28×COM4)
○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] (＊1)
DISCTL
(P1,P0)
Duty set (P3,P2)
(0,0)
(0,1)
(1,＊)
1/4duty 1/3duty 1/1duty
Duty set (P3,P2)
(0,0)
(0,1)
(1,＊)
1/4duty 1/3duty 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
*1: 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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10.Apr.2015 Rev.004