BU97941FV_15 Datasheet, PDF (10/27 Pages) Rohm – Multifunction LCD Segment Driver

BU97941FV MAX 104 segments (SEG26×COM4)
○Display control command (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 setting
Setting
1/4duty (1/3bias)
1/3duty (1/3bias)
Static (1/1bias)
(*: Don‟t care)
P3 P2 Reset state
00
○
01
1
*
At 1/3duty, the display / blink data for COM3 are invalid.
(COM3: same waveform with COM1)
At 1/1duty (Static), the display / blink data for COM1 to 3 are invalid.
(COM1 to 3: same waveform with COM0)
Be careful in sending display data.
For sample output waveform of SEG/COM with duty setting, see "Liquid crystal Display Waveform".
Frame Frequency Setting
Setting
(When 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
○
The relationship with frame frequency (FR), internal osc frequency and dividing number is below:
DISCTL
(P1,P0)
1/4duty
Divide
1/3duty
1/1duty
1/4duty
FR [Hz]
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
When calculating the OSC frequency from the measurement value of frame frequency, use the following equation:
“ OSC frequency = Frame Frequency (Measurement value) × Dividing number”
Dividing number：Using the values of Frame Frequency setting (P1,P0) and duty setting(P3,P2), determine the
values from the table above.
Ex) (P1,P0) = (0,1) 、(P3,P2) = (0,1) ⇒ Dividing number= 237
＊1：The value of FR in the table above is the Frame Frequency calcuated as OSC Frequency = 20.48KHz (typ).
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10.Apr.2015 Rev.004