Protocoll description LPR-2DB.pdf - Symeo

More documents

Recommendations

Info

SYMEO LPR ®Symeo 2D protocolprotocol descriptionprotocol by0x7d0x7e0x7f0x7d 0x5d0x7d 0x5e0x7d 0x5fFigure 3 – Substitution rules for byte stuffingEach time one of the three exclusive symbols occurs in the data packet it is replaced by twoother symbols. In the worst case the whole data packet consists of exclusive symbols. In thiscase the length of the data packet is doubled.The byte stuffing makes sure that the receiver can identify the BINARY-START fielddefinitively, even if the payload data contains the reserved symbol.Decoding the byte stuffing at the receiver side can be implemented as following:When reading symbol 0x7d, discard this symbol and combine the next symbol via XORfunctionwith 0x20, which will restore the original symbol.The byte stuffing can only be used for the binary format of the 2D protocol. It is activated perdefault. If you want to disable byte stuffing you have to enter in the configuration file thefollowing line:[DisableBytestuffing] 11.2.3 General StructureThe structure of the data packet of the 2D protocol is identified in the configuration file. Forone configuration all data packets have the same length and the same structure. In theconfiguration file you identify the desired data fields. Figure 4 shows the structure of the datapacket for the standard configuration.Data fieldSTARTPOSITIONENDFigure 4 - General structure of data packet with standard configurationIf required additional data fields can be activated. The sequence of the activated data fieldsis fixed and cannot be changed. Figure 5 shows the structure of the data packet with allactivated data fields.Data fieldSTARTCopyright © Symeo GmbH 2010Symeo 2D Protocolpage 6 of 25
SYMEO LPR ®Symeo 2D protocolprotocol descriptionTIMESTAMPPOSITIONVELOCITYORIENTATIONPOSITION-ERRORVELOCITY-ERRORORIENTATION-ERRORUSER-DATASYSTEM-ERRORSATELLITE-STATECRCENDFigure 5 - General structure with all possible data fieldsThe data fields START and END cannot be deactivated. All other data fields can be enabledand disabled in the configuration file.1.2.4 Data fieldsIn this chapter all data fields are described. Except the two data fields START and END(included in each data packet) each data field can be enabled and disabled by the user.The unit of data length is one byte.1.2.4.1 STARTThe data field START indicates the beginning of a data packet. It contains furthermore thedata length of the whole data packet. One bit mask indicates which data fields are enabled.Name Length Type DescriptionBINARY-START 1 unsigned int Exclusive Symbol 0x7e, which identify thebeginning of a data packetLENGTH 2 unsigned int Length of the entire data packet in byte(including the start and end field)SELECTED-FIELDSEntire length of data packet: 7 Byte4 bitmask The bit mask indicates which data fields areenabled and disabled in the data packet(see chapter 1.4).Symeo 2D ProtocolCopyright © Symeo GmbH 2010page 7 of 25
Page 1 and 2: Symeo 2D protocolSYMEO LPR ®
Page 9 and 10: SYMEO LPR ®Symeo 2D protocolprotoc
Page 25: SYMEO LPR ®Symeo 2D protocolprotoc

Protocoll description LPR-2DB.pdf - Symeo

Create successful ePaper yourself

Delete template?

Save as template?