Navctrl register – Rainbow Electronics AT77C105A User Manual

Page 17

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17

AT77C105A [Preliminary]

5419A–BIOM–01/05

1: watchdog enabled

Watchdog automatically stops heating of the sensor after a time-out.

HEATV (2 bits): Heating power value

00: 50 mW

01: 100 mW

10: reserved

11: reserved

V

DD

is between 2.5 and 3.6V.

Notes:

1. Heating can only be used in the acquisition mode (it is not allowed in navigation or

click modes).

2. The oscillator has to be activated when the watchdog is required and must not be

stopped while the watchdog remains active.

Navctrl Register

Register Name: Navctrl (7 bits)

Access Type: Read/Write

Function: Navigation control

NAVFREQ: Navigation frequency

00: 5.8 kHz

01: 2.9 kHz (default value)

10: 1.9 kHz

11: 1.5 kHz

A faster frequency enables faster finger movement detection. A lower frequency
enhances sensitivity. Refer to Notes 1 and 2 on page 18.

NAVV: Navigation pixels threshold

00: lower threshold

01:

10:

11: higher threshold

Sets the minimum analog value detected as a high level (‘1’). Refer to Note 1 on page
18.

CLICKV: Click pixels threshold

00: lower threshold

01:

10:

11: higher threshold

b6

b5

b4

b3

b2

b1

b0

NAVFREQ

(MSB)

NAVFREQ (LSB)

NAVV ( MSB)

NAVV (LSB)

CLICKV (MSB)

CLICKV (LSB)

reserved

1

0

0

0

0

0

0

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