Chapter 3
Operation of the GPIB-232CV-A
©
National Instruments Corporation
3-3
D Mode Overview
In D mode, the GPIB-232CV-A acts as another device on the bus.
Figure 3-3 shows the D mode system layout.
Figure 3-3.
D Mode System Layout
In D mode, the GPIB-232CV-A can act only as a GPIB Talker or Listener.
Do not pass control to the GPIB-232CV-A when using D mode. If you do,
the GPIB circuitry in the GPIB-232CV-A accepts control and immediately
asserts the ATN* signal, a system error condition that you should avoid.
Because the GPIB-232CV-A is not System Controller in D mode, it expects
to receive GPIB commands from the Controller-In-Charge (CIC). If the
GPIB-232CV-A receives the universal Device Clear (DCL) command or is
addressed to listen and receives the Selected Device Clear (SDC)
command, it clears its internal data buffers and resets to its power-up state.
Neither Trigger (GET) nor Go To Local (GTL) have any effect on the
GPIB-232CV-A.
Data Transfers in D Mode
When you are ready to send data to the GPIB-232CV-A in D mode, address
the GPIB-232CV-A to listen, if not already in listen-only mode. All GPIB
data received by the GPIB-232CV-A is buffered and passed along to the
serial device. When you are expecting to receive data from the serial
device, address the GPIB-232CV-A to talk, and all data received over the
serial port is passed along to the GPIB port.
PO
WER
READ
Y
TALK LISTEN
B
USY
FULL
GPIB-232CV-A
GPIB-232CV-A
Controller
Serial Device
FUSE
GPIB
Device
GPIB
Device
GPIB
Device