Operation Principle; Order Information - Velleman VMA329 User Manual

successful confirmation code; If there is no finger, returned confirmation code would be
"can't detect finger".
Input Parameter: none
Return Parameter: Confirmation code (1 byte)
Instruction code: 01H
Command (or instruction) package format:
Header Module address
2 bytes 4bytes
0xEF01 Xxxx
Acknowledge package format:
Header Module address
2 bytes 4bytes
0xEF01 Xxxx
Note: Confirmation code=00H: finger collection success;
Confirmation code=01H: error when receiving package;
Confirmation code=02H: can't detect finger;
Confirmation code=03H: fail to collect finger;
" 、 "Close Led"and "GetImageFree" ）
ZFM-70 series also retain the old command interface , use the old command, you can shark the light when
capturing fingerprint（Realize by use the command"GetImg" ） 。
 The faster response
By optimizing the image acquisition and pretreatment of the driver, the image acquisition and image
preprocessing process can save more time, better image quality, faster response speed.
 Power on handshake
When ZFM-70 series power on, it will send a byte(0x55) to handshake, then upper computer can send other
commands.
 single command to complete the enroll and search
ZFM-70 series add the commands "Autologin" and "AutoSearch" , in single command to complete the enroll
and search

1.3 Operation Principle

Fingerprint processing includes two parts: fingerprint enrollment and fingerprint matching (the matching can
be 1:1 or 1:N).
When enrolling, user needs to enter the finger two times. The system will process the two time finger images,
generate a template of the finger based on processing results and store the template. When matching, user enters
the finger through optical sensor and system will generate a template of the finger and compare it with templates
of the finger library. For 1:1 matching, system will compare the live finger with specifc template designated in the
Module; for 1:N matching, or searching, system will search the whole finger library for the matching finger. In
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ZFM-70 SeriesFingerprint Identification Module User Manual
Package Package length
identifier
1 byte 2 bytes
01H 0003H
Package Package length
identifier
1 byte 2 bytes
07H 0003H
8
Instruction code Checksum
1 byte 2 bytes
01H 05H
Confirmation code Checksum
1 byte 2 bytes
xxH Sum
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