NavCom LAND-PAK Rev.N - Manual (Page 41)

Technical Reference Manual Rev. N
Blk = All; Blu = IOP w/Internal Radio ; Red = IOP & LBM ; Grn = Engine only
39
0x21 - NMEA Data request - 4 + 2 + (4 x N) bytes
This message initiates a NMEA data request as decoded by words W1, W2, and Wn1 to Wn3.
NMEA Message ID’s (Refer to the section, NMEA Output Messages , for details.)
ALM 0x01
GGA 0x02
GLL 0x03
GSA 0x04
GSV 0x05
RMC 0x06 VTG 0x07
ZDA 0x08
GST 0x09
SET 0x0A
GBS 0x0B
MDE 0x0C NCTGST 0x0D
GRS 0x0E
Record
Usage Command - Yes
Response - No Input: Creates the output message list for the designated port; see NVRAM Storage
in previous section; Output:
Ref Message Field Description
Data
Type
Units Range Scale
Byte
Count
STX 02 (hex) U08 1
PRA1 99 (hex) U08 1
PRA2 66 (hex) U08 1
ID 21 (hex) U08 1
Length 0x00xx (variable) U16 2
W1
Command Action
B1=0: Do not store in NVRAM
1: Store in NVRAM
B6=0: Stow in user NVRAM
1: Store in factory NVRAM
B3=0: Use Commanded Values
1: Use Default values
B4=1: Clear Present NMEA Output Requests
U08 1
W2
For the ZDA record:
B7-B3: Local Hours Adjustment (Signed value)
B2-B1: Local Minutes Adjustment
B0=1: Use data in B7:B1, else ignore. Not set on
output
U08
hrs
min
+13
0,15,30,45 Lsb: 15
1
Repetitive Blocks
Wn1
NMEA Message ID (see below for assignment)
0x00: All currently active output messages if Data
Rate 0 then clear all commands
0x01 - 0xFF: Individual COMMAND IDs
U08 1
Wn2 Reserved U08 1
Wn3
Data rate
0x0001 to 0x1770: begin data output at this rate
Data rate – special (ALM not supported)
0x0000: output data at once, or else stop
ALM not supported
0x2000: output data on external trigger
Supports (GGA, GLL, RMC, VTG)
0x4000: output data at Navigation Rate
0x80nn: Output per SV (ALM only)
0 -- all SV’s
nn – Only Satellite nn
U16
sec 1-6000 x 1
2
CKSM Checksum U08 1
ETX 03 (hex) U08 1