BU21170MUV Datasheet, PDF (3/33 Pages) Rohm – Capacitive Switch Controller IC

BU21170MUV
Block Diagram
VDD
SDA
SCL
ADR
TEST
VSS
VREF
LDO15
OSC
LOGIC
AFE_CNT
MPU
HOST
I/F
WDTR
PROM
WRAM
LEDDRV
PWM_CNT
LDO28
POR
A/D
C/V
Converter
AFE
AVDD
DVDD
Sensor
AFE
SIN0-4
LED0-4
DTG
INT
Figure 6. Block Diagram
Block Descriptions
Sensor AFE , C/V Converter
Convert from capacitance to voltage following the order of sensors.
A/D
Convert from voltage to the detected result the digital value.
LDO28
2.73V output LDO for Sensor AFE, C/V Converter and A/D.
LDO15
1.5V output LDO for OSC and digital blocks.
OSC
Ring oscillator as the system clock.
POR
Power-On-Reset monitoring VDD as the system reset.
MPU
Based on the detection result, detect switch operations (Touch/Release/Hold) and run Auto-calibration.
Inform by the INT port to the host about that the switch operations are detected.
LED ports are controlled by the commands from the host.
HOST I/F
2-wire serial bus interface compatible with I²C protocol. Slave address is selectable by pin ADR.
AFE_CNT
Sequencer of Sensor AFE, C/V converter and A/D.
PWM_CNT
PWM timers for the LED ports.
LEDDRV
LED port drivers.
WDTR
Watchdog timer Timeout Reset. It releases the system reset after 0.6sec from that MPU cannot clear WDTR.
(If MPU cannot clear WDTR, MPU is hung up.)
PROM
Program ROM for the included MPU.
WRAM
Work RAM for the included MPU.
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TSZ02201-0L5L0F300830-1-2
14.Jul.2016 Rev.002