cy8cmbr2044 Cypress Semiconductor Corporation., cy8cmbr2044 Datasheet - Page 9

• Manufacturer Part Number: cy8cmbr2044
• Description: Capacitive Button Controllers
• Manufacturer: Cypress Semiconductor Corporation.

Flanking Sensor Suppression
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Failure Mode Analysis
A built-in Power On Self Test (POST) mechanism detects the
following at power on reset (POR), which can be useful in
production testing.
Sensor Shorted to Ground
If a sensor is disabled a 5 ms pulse is sent out on the corre-
sponding GPO within 175 ms of power on.
Figure 5. Sensor Shorted to Ground
Sensor Shorted to VDD
If any sensor is shorted to VDD that sensor is disabled and a
5 ms pulse is sent out on the corresponding GPO within 175 ms
of power on.
Figure 6. Sensor Shorted to VDD
Document Number: 001-57451 Rev. *C
Provides discrimination between closely spaced sensors
At any point of time, only one sensor is reported as ON
The first sensor touched is reported as ON until it is released, even if other sensors are pressed
Figure 4. Sensor Status with Respect to Finger Touch when FSS is Enabled
Sensor to Sensor Short
Any Sensors that are shorted together is disabled and 5ms pulse
is sent out on the GPOs of the shorted sensors within 175ms of
power on.
Figure 7. Sensor to Sensor Short
Proper Value of CMOD
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Sensor C
If the parasitic capacitance (C
that sensor is disabled and a 5 ms pulse is sent out on the
corresponding GPO within 175 ms of power on.
Recommended value of CMOD is 2 nF to 2.4 nF.
If CMOD of < 1 nF or > 4 nF is connected, all sensors are
disabled and a 5 ms pulse is sent out on all the GPOs within
175 ms of power on.
P
> 40 pF
P
) of any sensor exceeds 40 pF
CY8CMBR2044
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