User`s manual

46 Understanding the Agilent E1330B Digital I/O Module
Chapter 4
TRAiling Edge The TRAiling Edge handshake makes use of both the CTL and FLG lines.
The input and output operations are described below.
INPUT OUTPUT
1 The Digital I/O module senses the
FLG line and waits for READY.
1 The Digital I/O module checks the
state of the FLG line (must be
READY).
2 The Digital I/O module sets the
I/O
line HIGH.
2 The Digital I/O module sets the
I/O line LOW.
3 The Digital I/O module sets CTL
TRUE.
3 The Digital I/O module places the
data on the data lines.
4 The peripheral senses the CTL
line and sets the FLG line to
BUSY.
4 After waiting the programmed
delay time, Td, the Digital I/O
module sets CTL to TRUE.
5 The Digital I/O module senses the
FLG BUSY and sets the CTL line
FALSE.
5 The peripheral senses the CTL
line and sets the FLG line to
BUSY while it latches the data.
6 The peripheral senses the CTL
line change and places data on
the data lines.
6 The peripheral returns the FLG
line to READY indicating the end
of data transfer.
7 The peripheral indicates the data
is valid by returning the FLG line
to READY.
7 The Digital I/O module senses the
FLG line in the READY state and
returns CTL to FALSE.
8 The Digital I/O module senses the
FLG READY and latches the data.