
2317 Rev 1.1 (17NOV04)
AuthenTec Confidential Information
7
1.3
Conventions
For vectors (groups of bits), ordering will always be from MSB to LSB (e.g.
Pixel_Data[63:0] where bit 63 is the MSB and bit 0 is the LSB).
When vectors that span multiple bytes are transmitted, the lower byte (bits
[7:0]) is transmitted first. This applies to pixel data and the authentication
word returned after each imaging frame.
Numbers followed by a ‘b’ are shown in binary. Numbers followed by an
‘h’ are in hexadecimal.
1.4 Operational
Description
The Sensor begins operation in the ‘idle’ state after a reset. In the idle
state, array power is turned off and clocking is disabled (except to support
interface activity). It is then necessary for the system SW to program the
sensor for the desired operation (Imaging or Navigation). After this setup,
the requested operation is enabled by setting the Op Enable bit (located in
Register 80h:D2). If Imaging is selected, the Sensor enters finger detect
mode checks for a finger present at a rate programmed by the Finger
Detect Rate setting. The default reset value sets the detect period to ~62
ms.
After finger detection, the sensor will begin the programmed operation and
will enter Imaging mode until the finger is removed. Once the finger is
removed, the sensor returns to the Low Power Finger Detect mode.
When no activity is detected on the system interface bus for approximately
200uS, power is reduced by disabling the internal clocks and the array
power is once again turned off.
Figure 1-1
Row Numbering