Symbol SE 923, Integration Manual

Page: 201 / 238

A-5
Serial Interface Specification
IF (character was received) THEN
RETURN (FALSE) /* abort transmit */
END
END
disable receiving
remove host’s permission to send
END /* resume transmit */
END
RETURN (TRUE)
Receiving Data
The decoder can receive data whenever it grants permission to the host to send its data. If the
host is transmitting data, the maximum character-to-character delay allowed is determined
by the Host Intercharacter Time-out parameter. The decoder may discard any received data
if the host exceeds this time limit.
Sample Code for Decoder Receive Procedure
void decoder_receive()
IF (host is requesting to send) THEN
give host permission to send
WHILE (no characters received) DO
IF (host is no longer requesting to send) THEN
remove host’s permission to send
RETURN /* NULL xmit - do not NAK */