Datasheet

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
Revision 1.32 (01-05-12) 76 SMSC CAP1188
DATASHEET
The LED Breathe Period register determines the overall period of a breathe operation as determined
by the LED_CTL registers (see Table 5.52 - setting 11b). The LSB represents 32ms so that a setting
of 18h (24d) would represent a period of 768ms. The total range is from 32ms to 4.064 seconds (see
Table 5.54) with a default of 2976ms.
APPLICATION NOTE: Due to constraints on the LED Drive PWM operation, any Breathe Period less than 160ms
(05h) may not be achievable. The device will breathe at the minimum period possible as
determined by the period and min / max duty cycle settings.
5.35 LED Configuration Register
The LED Configuration register controls general LED behavior as well as the number of pulses that
are sent for the PULSE LED output behavior.
Bit 6 - RAMP_ALERT - Determines whether the device will assert the ALERT# pin when LEDs
actuated by the LED Output Control register bits have finished their respective behaviors. Interrupts
will only be generated if the LED activity is generated by writing the LED Output Control registers. Any
LED activity associated with touch detection will not cause an interrupt to be generated when the LED
behavior has been finished.
‘0’ (default) - The ALERT# pin will not be asserted when LEDs actuated by the LED Output Control
register have finished their programmed behaviors.
‘1’ - The ALERT# pin will be asserted whenever any LED that is actuated by the LED Output
Control register has finished its programmed behavior.
Bits 5 - 3 - PULSE2_CNT[2:0] - Determines the number of pulses used for the Pulse 2 behavior as
shown in Table 5.58.
Bits 2 - 0 - PULSE1_CNT[2:0] - Determines the number of pulses used for the Pulse 1 behavior as
shown in Table 5.58.
Table 5.57 LED Configuration Register
ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT
88h R/W LED Config -
RAMP_
ALERT
PULSE2_CNT[2:0] PULSE1_CNT[2:0] 04h
Table 5.58 PULSEX_CNT Decode
PULSEX_CNT[2:0]
NUMBER OF BREATHS2 1 0
0 0 0 1 (default - Pulse 2)
0 0 1 2
0 1 0 3
0 1 1 4
1 0 0 5 (default - Pulse 1)
1 0 1 6
1 1 0 7