Mindeo FS580 - Transfer of Decode Data

97
6-2 Transfer of decode data
The parameter of Decode Data Packet Format (see “4-3 RS232 interface”) controls how decode data is
sent to the host. When Decode Data Packet Format is set as Packeted, the data is sent in a
DECODE_DATA packet. When Decode Data Packet Format is set as Raw, the data is transmitted as
raw ASCII data.
When decode data is transmitted as raw ASCII data, ACK/NAK handshaking does not apply regardless
of the state of the ACK/NAK handshaking parameter.
a) Flow control=ACK/NAK, Decode Data Packet Format=Packeted
The scanner sends a DECODE_DATA packet message after a successful decode. The scanner waits
for a programmable time-out for a CMD_ACK response. If it does not receive the response, the scanner
tries to send twice more before issuing a host transmission error.
If the scanner receives a CMD_NAK from the host, it may attempt a retry depending on the cause field of
the CMD_NAK message.
Scanner Host
(1)
DECODE_DATA packet
(2)
CMD_ACK
b) Flow control=ACK/NAK, Decode Data Packet Format=Raw
Even though the ACK/NAK handshaking is enabled, no handshaking occurs because the handshaking
applies only to packet data.
Scanner Host
Raw ASCII Data
c) Flow control≠ACK/NAK, Decode Data Packet Format=Packeted
In this example ACK/NAK does not occur because the ACK/NAK handshaking parameter is disabled.
Scanner Host
DECODE_DATA packet
d) Flow control≠ACK/NAK, Decode Data Packet Format=Raw
Data is captured.
Scanner Host
Raw ASCII Data