BU21009MUV-E2 ROHM Electronics, BU21009MUV-E2 Datasheet - Page 12

• Manufacturer Part Number: BU21009MUV-E2
• Description: Specifications: Type: Capacitive ; Touch Panel Interface: 1, 2-Wire ; Data Interface: Serial ; Lead Free Status: Lead Free ; RoHS Status: RoHS Compliant
• Manufacturer: ROHM Electronics

●Operation mode
●Interface and system clock selection
●Initialization procedure
●Power supply turning on procedure
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BU21009MUV
www.rohm.com
【FDh : Switch ON -> OFF Threshold Value】
【FEh : LED Port Data】
This IC has a normal mode, idle mode and a shutdown mode as states of operation.
【Normal mode】
【Idle mode】
【Shutdown mode】
I/F selection with MODE [1:0] pin. System clock selection by RXD.
【Using 2wires serial bus mode (MODE［1:0］＝00b)】
A normal power on sequence is:
You should always power on DVDD at the same time as AVDD or before AVDD.
Initial val.
Initial val.
Name:
Address:
Description:
Name:
Address:
Description:
This is the normal operation of the device. Output pin INT="L".
This is the mode when the normal mode times out due to inactivity on the keys. In this mode the control interface is still
alive.
In this mode the device is completely stopped – and reset. This is achieved by making the terminal SDN L. All analog
circuits and the logic circuits are stopped. The return from the shutdown mode returns by making the terminal SDN H.
The 2wires serial bus is used for host I/F.
RXD=0 in the system clock: Built-in oscillator is used.
RXD=1 in the system clock: The clock input from CLK_EXT is used.
(1) Power on
(2) Setup the registers
(3) Write ‘1’ to 0xEF (done register)
FDh
R/W
R/W
FEh
*Usually time-out is aimed at about 200msec or less.
*Transition between normal and idle modes is automatic and without software control.
*After shut-down all registers have their default values.
<sensing operation begins after auto-calibration occurs>
This register provides a threshold value for transitioning from ON to OFF.
This is relative value from reference value (128d). So absolute value of threshold is128d + OFF[6:0].
It makes a threshold value between TH_ON and TH_OFF.
TH_OFF must be smaller than TH_ON (TH_OFF =< TH_ON)
Maximum value is 256d and minimum value is 128d.
When LED is not linked with the sensor, it becomes a simple digital output that controls the LED.
1 : Light. 0 : Turned off.
Bit7
Bit7
TH_OFF
FDh
DLED
FEh
D7
W
0
-
-
-
OFF[6]
Bit6
Bit6
D6
W
W
0
0
OFF[5]
Bit5
Bit5
D5
W
W
0
0
OFF[4]
Bit4
Bit4
D4
12/13
W
W
0
0
OFF[3]
Bit3
Bit3
D3
W
W
0
0
OFF[2]
Bit2
Bit2
D2
W
W
0
0
OFF[1]
Bit1
Bit1
D1
W
W
0
0
Technical Note
2009.04 - Rev.B
OFF[0]
Bit0
Bit0
D0
W
W
1
0