The Flg Line (Input); The Ctl Line (Output) - Keysight VXI Bus 75000 C Series User And Programming Manual

Using the Keysight E1458A Digital I/O Module
POSitive Polarity
NEGative Polarity
The data lines in each port, as a group, can be set to use an internal +5 Vdc
pull-up during output operations. Additionally, the UTS control line can force all
the data lines in a port to the three-state condition (non-sourcing).

The FLG Line (Input)

Each port has a flag (FLG) line. A flag line is an input line from a peripheral and
has two states, READY and BUSY. A flag line is normally used in conjunction with
the corresponding control line (CTL) to establish a handshake between a
peripheral and the digital I/O module. SCPI commands that define handshake
modes typically use the FLG and CTL lines. The state of the FLG line can also be
read with a SCPI command to implement custom handshakes. Positive polarity is
the default. The following shows the effect of changing the polarity of the FLG
line:

The CTL Line (Output)

Each port has a control line (CTL). A control line is an output line from the digital
I/O module to the peripheral and has two states, TRUE and FALSE. A control line
is normally used in conjunction with the corresponding flag line on the same port
to establish a handshake between a peripheral and the digital I/O module. SCPI
commands that define handshake modes typically use the FLG and CTL lines.
The state of the CTL line can be read and set with SCPI commands to implement
custom handshakes. Positive polarity is the default. The following shows the
effect of changing the polarity of the CTL line:
POSitive Polarity
NEGative Polarity
28
Input Operations
TTL High = 1
TTL Low = 0
TTL High = 0
TTL Low = 1
POSitive Polarity
NEGative Polarity
TTL High = BUSY = 1
TTL Low = READY = 0
TTL High = READY = 0
TTL Low = BUSY = 1
TTL High = TRUE = ON = 1
TTL Low = FALSE = OFF = 0
TTL High = FALSE = OFF = 0
TTL Low = TRUE = ON = 1
Keysight E1458A 96-Channel Digital I/O Module User Guide
Port Description
Output Operations
1 = TTL High
0 = TTL Low
0 = TTL High
1 = TTL Low