SFG R303A Series, Руководство пользователя, Страница: 6 / 24

V
IH
2.4 V Logic 1
V
IH
=5V 1 mA
I
IH
V
IH
=3.3V 30 uA
V
Imax
－
0.3 5.5 V
Maximum input voltage
IV System Resources
To address demands of different customer, Module system provides abundant resources at user’s
use.
Notepad
The system sets aside a 512-bytes memory (16 pages* 32 bytes) for user’s notepad, where data
requiring power-off protection can be stored. The host can access the page by instructions of
PS_WriteNotepad and PS_Read Notepad.
Note: when write on one page of the pad, the entire 32 bytes will be written in wholly covering the
original contents.
Buffer
There are an image buffer and two 512-byte-character-file buffer within the RAM space of the
module. Users can read & write any of the buffers by instructions.
Note: Contents of the above buffers will be lost at power-off.
Image buffer
ImageBuffer serves for image storage and the image format is 256*288 pixels.
When transferring through UART, to quicken speed, only the upper 4 bits of the pixel is transferred
(that is 16 grey degrees). And two adjacent pixels of the same row will form a byte before the
transferring. When uploaded to PC, the 16-grey-degree image will be extended to 256-grey-degree
format. That’s 8-bit BMP format.
When transferring through USB, the image is 8-bit pixel, that’s 256 grey degrees.
Character file buffer
Character file buffer, CharBuffer1, CharBuffer2, can be used to store both character file and
template file.
4.3
Fingerprint Library
Synstem sets aside a certain space within Flash for fingerprint template storage, that’s fingerprint
library. Contents of the library remain at power off.
Capacity of the library changes with the capacity of Flash, system will recognize the latter
automatically. Fingerprint template’s storage in Flash is in sequential order. Assume the fingerprint
capacity N, then the serial number of template in library is 0, 1, 2, 3 … N. User can only access
library by template number.
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