BU21072MUV_16 Datasheet, PDF (27/40 Pages) Rohm – Capacitive Switch Controller ICs

BU21072MUV / BU21078MUV / BU21078FV
Interrupt of PWM continuous flashing
When PWM configuration is set to not always lights, PWM drive repeat as many times as the setting value. The
interrupt is released at finishing PWM drive. In the case of that LED always lights, the way to turn LED off is to write to
„0‟ to the LED port register. And the interrupt of PWM continuous flashing of LED finish is not issued.
Start timing of next PWM continuous flashing can set after outputted the interrupt of PWM continuous flashing of LED.
Case of finished for the interrupt is not output, please send starting command (write “1” to 0xFA register bit) after the
wait for more than (falling time) + (Lighting-OFF time). Starting command is invalid case of wait for less than (falling
time) + (Lighting-OFF time).
Figure 25. Interrupt of PWM drive
0xED(PWM LED-PWM setting allocation) = 1 -> PWM0 allots to LED0 and LED1
Bit0 control of 0xFA (LED control)
Bit1 control of 0xFA (LED control)
First OFF→ON
PWM0 timer wave
LED0 output wave
Last ON→OFF
Falling is begun because of
Last ON -> OFF is detected.
Turn ON time is shortening.
LED1 output wave
When PWM timer allots to some LED pins, First OFF -> ON turned LED control bit recognizes at start trigger of PWM timer (Other LED control bits allotted same
PWM are all 0). Last ON -> OFF turned LED control bit recognizes at stop trigger of PWM timer (Other LED control bits allotted same PWM are all 0).
When PWM timer is operating, Other LED control bit is '1' = PWM timer wave is output. Other LED control bit is '0' = LED is OFF (Remove Last ON -> OFF).
Case of last ON -> OFF, It treats PWM start/stop.
Forbid control
Bit0 control of 0xFA (LED control)
Bit1 control of 0xFA (LED control)
First OFF→ON
The same time,
It is considered to be last ON -> OFF,
one side : ON -> OFF _→ LED0 outputs PWM timer0 wave.
one side : OFF -> ON
LED1 is in effect steadily OFF as stop aperation.
PWM0 timer wave
LED0 output wave
LED1 output wave
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14.Jul.2016 Rev.004