NavCom LAND-PAK Rev.N User Manual
Page 105
Technical Reference Manual Rev. N
Blk = All;
Blu = IOP w/Internal Radio
;
Red = IOP & LBM
;
Grn = Engine only
103
To retrieve a file from the file system, the desired file must first be opened to read. Specify
an Open File for Reading request with the desired file name. Only one file may be open for
reading at a time. If a file is open for reading, and an Open File for Reading request is
received by the IOP, a response is sent with bit 1 of W3 set to 1 (“can’t open file for
reading”). If the requested file is not present, bit 0 of W3 is set to 1 (“no such file”).
A successful Open File for Reading request / response includes a 16-bit file handle used in
subsequent manipulation of the file via messages 0x7e.0x09 and 0x7e.0x0a (File Record
Request and Close File, respectively).
With a successful command (i.e. a response with result code = 0), request the contents of
the file one sector (512 bytes) at a time using message 0x7e.0x09 (File Record Request),
by consecutively requesting sectors 0 through (File Size in Sectors – 1) inclusive.
After the file has been completely retrieved, send message 0x7e.0x0a (Close File).
Request
Record
Usage
Command - Yes
Response - No
Input: Open file reading request;
Output: see table below
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
7e(hex)
U08
1
Length 0xXXXX
U16
2
W1
Sub ID 0x08
U08
1
W2
0x00 (request)
U08
1
W3
Reserved
U16
2
W4
Filename – Null terminated String
U08
1
CKSM Checksum
U08
1
ETX
03
(hex)
U08
1
Response
Record
Usage
Command - No
Response - Yes
Input: see table above;
Output: reports the current deleted file directory
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
7e(hex)
U08
1
Length 0xXXXX
U16
2
W1
Sub ID 0x08
U08
1
W2
0xff (response)
U08
1