2317 Rev 1.1 (17NOV04)
AuthenTec Confidential Information
20
4.5 Timing
Information
.
4.5.1 Image Scan Timing
The fastest scan time available is 32us per sixteen pixels and will limit
image frame rates to less than [16x192 pixels * 32us/16 pixels = 6.144
ms] or ~162.7 fps maximum. Transferring register data, histogram data,
and authentication data will reduce this frame rate.
4.5.2 USB
Interface
The AES2501A fingerprint sensor is as a USB low power device. This
requires that the total current consumption be less than 100 mA and
suspend current be less than 500uA. For all timing diagrams, please refer
to the Universal Serial Bus Specification, Version 2.0
.
The AES2501A
fully supports the USB selective suspend mode (C3 power state).
4.5.3 Finger Detect Auto-calibration
When using Finger Detect [delay method], the device is automatically
calibrated once on power up. Sending a master reset to the device does
not affect the setting of the reference delay value used for the finger
detect calculation. If desired, the device can be re-calibrated by setting
the Recalibrate FD bit [Reg82-D2], which is self-clearing.