CAP1298 datasheet(27/68 Pages) MICROCHIP

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DS00001571B-page 27

CAP1298

If more than one power state bit is set, the actual power state will be as shown in Table 5-3, "Power State Bit Overrides".

Bits 7 - 6 - GAIN[1:0] - Controls the analog gain used by the capacitive touch sensing circuitry. As the gain is increased,

the effective sensitivity is likewise increased as a smaller delta capacitance is required to generate the same delta count

values. The sensitivity settings may need to be adjusted along with the gain settings such that data overflow does not

occur.

APPLICATION NOTE: The GAIN[1:0] settings apply to both Standby and Active states, unless the COMBO bit is

set. When the COMBO bit is set, this control only applies to the sensors enabled in the

Active state, and the C_GAIN[1:0] control applies to the sensors enabled in the Standby

state.

APPLICATION NOTE: Whenever the gain settings change, the device will recalibrate all sensor inputs as if they

had no base count.

Bit 5 - STBY - Enables Standby.

• ‘0’ (default) - The device is not in the Standby state.

• ‘1’ - The device is in the Standby state. Capacitive touch sensor input scanning is limited to the sensor inputs set in

the Standby Channel register (see Section 5.21, "Standby Channel Register"). The status registers will not be

cleared until read. Sensor inputs that are no longer sampled will flag a release and then remain in a non-touched

state.

Bit 4 - DSLEEP - Enables Deep Sleep.

• ‘0’ (default) - The device is not in the Deep Sleep state.

• ‘1’ - The device is in the Deep Sleep state. All sensor input scanning is disabled. The status registers are automat-

ically cleared and the INT bit is cleared..

Bits 3 - 2 - C_GAIN[1:0] - When the COMBO bit is set, this bit controls the analog gain used for capacitive touch sensor

inputs enabled in the Standby state. As the gain is increased, the effective sensitivity is likewise increased as a smaller

delta capacitance is required to generate the same delta count values. The Standby sensitivity settings may need to be

adjusted along with the gain settings such that data overflow does not occur.

TABLE 5-3:

POWER STATE BIT OVERRIDES

DSLEEP

COMBO

STBY

Power State

Active

Standby

Combo

DSleep

TABLE 5-4:

GAIN AND C_GAIN BIT DECODE

GAIN[1:0] or C_GAIN[1:0]

Capacitive Touch Sensor Input Gain

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