BU21072MUV_16 Datasheet, PDF (4/40 Pages) Rohm – Capacitive Switch Controller ICs

BU21072MUV / BU21078MUV / BU21078FV
Block Diagram
VDD
SDA
SCL
TEST
VREF
LDO15
OSC
LOGIC
MPU
AFE_CNT
LDO28
POR
A/D
C/V
Converter
PROM
WRAM
HOST
I/F
WDTR
PWM_CNT
LEDDRV
AFE
AVDD
DVDD
Sensor
AFE
SIN*
LED*
INT
VSS
Figure 8. Block Diagram
Description of Blocks
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.
PROM
Program ROM for the included MPU.
WRAM
Work RAM for the included MPU.
HOST I/F
2-wire serial bus interface compatible with I2C protocol.
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 Reset. It releases the system reset after 1 sec from that MPU cannot clear WDTR.
(If MPU cannot clear WDTR, MPU is hang-up.)
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14.Jul.2016 Rev.004