Bourgogne ET Grasset SAS VEGRDE2 用户手册
Vegas Long Range Read/Write Device
27-07-2002
Vegrde3/EG
Confidentiality Level 1
Page 8 (48)
Bourgogne et Grasset -– ZI Beaune Savigny -– 21200 Beaune – France – Tel. +33 380 26 26 26 – Fax. +33 3 80 26 26 00
3.
Serial Protocol and Command Set
3.1.
Interface HITAG Read/Write Device
⇔ HOST
The device communicates with the host (processor, PC, ...) via serial interface using a baud rate
of 9600 baud. Data transfer details are: 1 start bit, 8 data bits, 1 stop bit and no parity bit, Least
Significant Byte is sent first.
of 9600 baud. Data transfer details are: 1 start bit, 8 data bits, 1 stop bit and no parity bit, Least
Significant Byte is sent first.
3.1.1. General
Definitions
The individual blocks show a common structure. Each block starts with the block length,
followed by a block title (function number or status) and then the data. The data are transmitted
transparently, i.e. you can use any character between 0x00 and 0xFF. Finally there is a check
sum which is formed as EXOR - link of all transferred data.
General Data Transfer Format:
Byte 1
2
3 4 ...... n
Function block length block title / status
data
data
.........
check sum
Block length is the sum of all transferred bytes including block length but excluding check sum.
The check sum is calculated by bytes 1 to n-1.
Data bytes only are transmitted if data is transferred.
Transfer timeout intervals are defined as follows:
a)
Character Delay
Character delay is the maximum time permitted to elapse between sending two consecutive
characters of a block.
characters of a block.
Character Delay
≤ 150 ms
b) Block
Delay
There must be a minimum interval - defined as block delay - between two blocks sent, to
allow for re-synchronization in case of malfunction.
allow for re-synchronization in case of malfunction.
Block Delay
≥ 160 ms
This block delay is only necessary if an error has occurred in the serial communication.