CAP1208 datasheet(41/67 Pages) MICROCHIP

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8-Channel Capacitive Touch Sensor

Datasheet

 2014 Microchip Technology Inc.

DS00001570B-page 41

Bits 3 - 2 - SAMP_TIME[1:0] - Determines the time to take a single sample as shown in Table 5.18.

Sample time affects the magnitude of the base counts, as shown in Table 4.1, "Ideal Base Counts".

Bits 1 - 0 - CYCLE_TIME[1:0] - Determines the desired sensing cycle time for channels enabled in the

Active state, as shown in Table 5.19. All enabled channels are sampled at the beginning of the sensing

cycle. If additional time is remaining, the device is placed into a lower power state for the remainder

of the sensing cycle.

APPLICATION NOTE: The programmed sensing cycle time (CYCLE_TIME[1:0]) is only maintained if the actual time

to take the samples is less than the programmed cycle time. The AVG[2:0] bits will take

priority, so the sensing cycle time will be extended as necessary to accommodate the

number of samples to be measured.

128

Table 5.18 SAMP_TIME Bit Decode

SAMP_TIME[1:0]

SAMPLE TIME

320us

640us

1.28ms (default)

2.56ms

Table 5.19 CYCLE_TIME Bit Decode

CYCLE_TIME[1:0]

PROGRAMMED SENSING CYCLE

TIME

35ms

70ms (default)

105ms

140ms

Table 5.17 AVG Bit Decode (continued)

AVG[2:0]

NUMBER OF SAMPLES TAKEN

PER MEASUREMENT

CAP1208 数据表(PDF) 41 Page - Microchip Technology