ZFM-70 SeriesFingerprint Identification Module
User Manual
www.zhiantec.com
Hangzhou Zhian Technologies Co.,Ltd
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IV System Resources
To address demands of different customer, Module system provides abundant resources at user’s use.
4.1
Buffer
There are an 72K-byte 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.
4.1.1
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.
4.1.2 Character file buffer
Character file buffer, CharBuffer1, CharBuffer2, can be used to store both character file and template file.
4.2
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.
4.3
System Confiuration Parameter
To facilitate user’s developing, Module opens part system parameters for use. And the basic instructions are
SetSysPara & ReadSysPara. Both instructions take Parameter Number as parameter.
When upper computer sends command to modify parameter, Module first responses with original
configurations, then performs the parameter modification and writes configuration record into Flash. At the next
startup, system will run with the new configurations.
4.3.1 Baud rate control (Parameter Number: 4)
The Parameter controls the UART communication speed of the Modul. Its value is an integer N, N= [1, 12].
Cooresponding baud rate is 9600*N bps
。
4.3.2 Security Level (Parameter Number: 5)
The Parameter controls the matching threshold value of fingerprint searching and matching. Security level is
divided into 5 grades, and cooresponding value is 1, 2, 3, 4, 5. At level 1, FAR is the highest and FRR is the
