Datalogic GWY-01-PBS-01, Справочное руководство

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GWY-01-PBS-01
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5.4.5 Application Data Buffer
The Application data buffer holds the CBx commands with the syntax explained in chapter 4.
5.5 EXAMPLES OF PROFIBUS COMMAND/RESPONSE MECHANISM
As seen in par. 5.3, there are two buffers – an OUTPUT Buffer that is controlled by the
MASTER, and an INPUT Buffer that is controlled by the slave (the Gateway).
The
OUTPUT Buffer is mapped the following way:
Output Buffer
Byte #
00: OUTPUT BUFFER CONTROL BYTE (OBCB)
01: (Always 0)
02: Packet Length in Bytes
03:
04:
05:
06:
07:
08:
09:
10:
-
-
N-2:
Packet Bytes (Command)
“ “
“ “
“ “
“ “
“ “
“ “
“ “
“ “
“ “
“ “
N-1: Data Consistency Byte (OBDCB)
Byte 0 is the Output Buffer Control Byte . The Master uses the lowest two bits of this byte
for handshaking: to signal that a command is ready for the slave ( Bit 1 ), and to acknowledge
receiving a response from the slave ( Bit 0 ).
OUTPUT BUFFER CONTROL BYTE
7 6 5 4 3 2 1 0
[1]
[0] [0] [0] [0]
[0] [0] [0]
Bit 0 is toggled by the Master to acknowledge a packet (response) from the RFID
Controller.
Bit 1 is toggled by the Master when it has a packet (command) ready for the RFID
Controller.
Bit 2 is set when the Master wishes to initiate a “Resynchronization” with the Slave,
and then cleared when it sees the corresponding handshake from the Slave,
(indicating that the resynchronization is complete).