BU97931FV Datasheet, PDF (17/32 Pages) Rohm – Multifunction LCD Segment Driver

BU97931FV MAX 112 segments (SEG28×COM4)
○OSC external input command (OSCSET)
MSB
LSB
D/C D6 D5 D4 D3 D2 D1 D0 Hex
1st byte Command
1
0
0
1
1
0
0
0 98h
2nd byte Command
0
0
0
0
0 P2 P1 P0
-
Reset
-
00h
Sets the type of clock mode. There are 4 selectable modes including external clock input mode.
Details of this command function are as follows.
Condition
Internal CLK (PWM generation OFF)
External CLK input for PWM (PWM generation OFF)
Internal CLK (PWM generation ON）
External CLK input for PWM (PWM generation ON)
External CLK input for Display (ROHM use only)
(*: Don’t care)
P2 P1 P0
0
0
0
0
0
1
0
1
0
0
1
1
1
*
*
Reset state
○
(P2,P1,P0)=(0,0,1): External PWM input mode
CLKIN：external PWM input available.
PWMOUT: “L” Output
*under the (P2,P1,P0)=(0,0,0) condition PWMOUT into same state
(P2,P1,P0)=(0,1,0) : PWM is generated from an internal oscillating frequency
(P2,P1,P0)=(0,1,1) : PWM is generated from an External CLK input from CLKIN
PWM width is set up by PWMSET and PWMSET command.
In case LED is used as back light of LCD panel and PWM is generated from internal clock, display flickering will
occur. In this case, please use under the PWM width ALL ”L” or ALL “H”setting only.
The relation of OSC function control by each command is as follows:
CLKIN terminal
External clock
External PWM
Integrated OSC
PWM
generation
OSCSET
command
PWMSET
command
Figure 10. OSC External Input
LED
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TSZ02201-0A0A2D300070-1-2
10.Apr.2015 Rev.004