UNICORECOMM Unicore, Command Reference Manual

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Command and Log Reference
42
ID Field Description Symbol Example
(E = East, W = West)
13 mode ind
Positioning mode indicator:
A = Autonomous mode
D = Differential mode
E = Estimated (dead reckoning) mode
M = Manual input mode
S = Simulator mode
N = Data not valid
a A
14 *xx Checksum *hh *72
15 [CR][LF] Sentence terminator [CR][LF]
6.2 Binary Information
Binary messages are strictly machine readable format and are ideal choice for
application of large amount data transmission. Since the inherent compression format,
binary message has much smaller data amount compared to ASCII, so the
communication ports of the receiver are able to transmit or receive more data. Binary
format is difined as below.
Basic Format:
Header 3 Sync bytes plus 24 bytes of header information. The header length is
variable as fields may be appended in the future. Always check the header length.
Data variable
CRC 4 bytes
The 3 Sync bytes fixed as
Table 6-14
:
Table 6-14: The 3 Sync Bytes Values
Byte Hex Decimal
First 0xAA 170
Second 0x44 68
Third 0xB5 181
This CRC applies to all data, including 32-bit CRC of the header.
Binary and ASCII header format for reference as follows:
Table 6-15: Binary Message Header Structure
ID Field Type Description
Binary
Bytes
Binary
Offset
1 Sync Char Hexadecimal 0xAA 1 0
2 Sync Char Hexadecimal 0x44 1 1
3 Sync Char Hexadecimal 0xB5 1 2
4 CPU Idle Uchar
Time the processor is idle,
between 0 and 100
1 3