pca8885 NXP Semiconductors, pca8885 Datasheet - Page 23

• Manufacturer Part Number: pca8885
• Description: Capacitive 8-channel Proximity Switch With Auto-calibration And Very Low Power Consumption
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA8885
Objective data sheet
Figure 25 on page 34
circuits.
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The 7-bit I
applied to pin A0 (V
two PCA8885 can be addressed on the same bus without the need for different hard
coded I
The sensor activity can be synchronized, so that interference between the sensors of
the different chips is avoided. One chip is considered to be the primary-chip. It
provides the sample clock on pin CLK_OUT. The other chip is considered to be the
secondary-chip. It uses the clock provided by the primary-chip instead of the internal
clock. The primary-chip samples the sensors on the rising edge of the internal sample
clock. The CLK_IN signal is inverted to derive the sample clock in the secondary-chip.
Therefore the secondary-chip samples its sensors on the negative edge of the sample
clock of the primary-chip. In this way, no simultaneous sensor sampling occurs.
Primary-chip or secondary-chip modes are enabled by programming the configuration
register (see
The interrupt signal can be cascaded. The INT output of the primary-chip can be
connected to the INT_IN input of the secondary-chip. The INT output of the
secondary-chip is then an OR’ed combination of the two interrupts.
If two devices are cascaded and the int-over-I
to put the secondary-chip in int-over-I
interrupt over the INT output to the INT_IN input of the secondary-chip.
2
C addresses.
2
C address consists of 6 fixed bits and 1 selectable bit. The level externally
All information provided in this document is subject to legal disclaimers.
Table 6 on page
Rev. 1 — 24 November 2011
illustrates a typical example of an application using two PCA8885
DD
Capacitive 8-channel proximity switch with auto-calibration
or V
SS
) defines the LSB of the I
10).
2
C mode. The primary-chip still signals an
2
C mode is desired, then it is sufficient
2
C slave address. In this way,
PCA8885
© NXP B.V. 2011. All rights reserved.
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