User's Manual

Table Of Contents
If the LRP830 encounters a fault it will respond with the following:
Field
Number of ASCII
Characters Content
Header 2 <STX><STX> (02H, 02H)
Response Size 4 Packet length in bytes excluding the header, response size,
checksum and terminator bytes.
Error Flag 2 FFH
Error Code 2 Hex error code, see Table 11 for details
Checksum 2 Optional checksum
Terminator 1 <ETX> (03H)
Most RF operations will also require additional parameters and data that will
be included in the command stream between the command code or echo and
the terminator.
The Header and Terminator are always STX and ETX respectively. Any
other field value is in ASCII hex notation. Allowed values: '0'-'9', 'A'-'F'. Ex-
ample: the value ABH (decimal 171) in ASCII protocol is transmitted as a
2-character string «AB», i.e. the 2 bytes: 41H 42H (ASCII values for 'A' and
'B'). The hex value of the hex digits given in ASCII are: '0'-'9' = 30H - 39H,
'A'-'F' = 41H-46H.
The sequence for each command is given with the response format in the
preceding section. Referring to the ABx Fast command you can structure the
ABx ASCII commands by using ASCII values for each digit of the hex val-
ues, excluding the header and terminator that are already ASCII characters.
Command/Response Size
The ABx ASCII requires the length of the packet be included in the com
-
mand. All parameters and data between the Command Size and the termi
-
nator or checksum byte must be accounted for in the packet size word. This
includes all command codes and parameters such as field definition for
Block Read/Writes. The packet size remains the same with, or without the
checksum.
Copyright © 2000 Escort Memory Systems
LRP830-Series Long-Range Passive Reader/Writer
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