When a multi byte message such as "FL1Z0R3" is sent
from a talker to a listener, the listener needs to have some way to
know when the message is complete and the last byte has been sent.
The end of message signal is given by requiring the talker to assert the End Or Identify (EOI) line as the last byte of the message is placed on the data lines. The reason for the EOI line's strange name is that it's a dual purpose line. In addition to signaling the end of a message, it's also used to initiate a parallel poll (see below). Another technique used by some GPIB instruments is to indicate the end of message by sending an ASCII line feed character (= Oah) as the last byte.
The end of message signal is given by requiring the talker to assert the End Or Identify (EOI) line as the last byte of the message is placed on the data lines. The reason for the EOI line's strange name is that it's a dual purpose line. In addition to signaling the end of a message, it's also used to initiate a parallel poll (see below). Another technique used by some GPIB instruments is to indicate the end of message by sending an ASCII line feed character (= Oah) as the last byte.
Wed, 2010-09-01 14:08
- Login or register to post comments
»