Datasheet

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
SMSC CAP1188 77 Revision 1.32 (01-05-12)
DATASHEET
5.36 LED Duty Cycle Registers
The LED Duty Cycle registers determine the minimum and maximum duty cycle settings used for the
LED for each LED behavior. These settings affect the brightness of the LED when it is fully off and
fully on.
The LED driver duty cycle will ramp up from the minimum duty cycle to the maximum duty cycle and
back down again.
APPLICATION NOTE: When operating in Direct behavior mode, changes to the Duty Cycle settings will be applied
immediately. When operating in Breathe, Pulse 1, or Pulse 2 modes, the LED must be
unactuated and then re-actuated before changes to behavior are processed.
Bits 7 - 4 - X_MAX_DUTY[3:0] - Determines the maximum PWM duty cycle for the LED drivers as
shown in Table 5.60.
Bits 3 - 0 - X_MIN_DUTY[3:0] - Determines the minimum PWM duty cycle for the LED drivers as
shown in Table 5.60.
1 1 1 8
Table 5.59 LED Duty Cycle Registers
ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT
90h R/W
LED Pulse 1
Duty Cycle
P1_MAX_DUTY[3:0] P1_MIN_DUTY[3:0] F0h
91h R/W
LED Pulse 2
Duty Cycle
P2_MAX_DUTY[3:0] P2_MIN_DUTY[3:0] F0h
92h R/W
LED Breathe
Duty Cycle
BR_MAX_DUTY[3:0] BR_MIN_DUTY[3:0] F0h
93h R/W
Direct Duty
Cycle
DR_MAX_DUTY[3:0] DR_MIN_DUTY[3:0] F0h
Table 5.60 LED Duty Cycle Decode
X_MAX/MIN_DUTY [3:0]
MAXIMUM DUTY
CYCLE
MINIMUM DUTY
CYCLE3 2 1 0
0 0 0 0 7% 0%
0 0 0 1 9% 7%
0 0 1 0 11% 9%
0 0 1 1 14% 11%
0 1 0 0 17% 14%
Table 5.58 PULSEX_CNT Decode (continued)
PULSEX_CNT[2:0]
NUMBER OF BREATHS2 1 0