R&S AFQ100A Operating Manual page 360

R&S AFQ100A
Bus Lines
1. Data bus with 8 lines D0 to D7
The transmission is bit-parallel and byte-serial in the ASCII/ISO code. D0 is the least significant bit, D7
the most significant bit.
2. Control bus with 5 lines
IFC
(Interface Clear)
ATN
(Attention)
SRQ
(Service Request)
REN
(Remote Enable)
EOI
(End or Identify)
3. Handshake bus with three lines
DAV
(Data Valid)
NRFD
(Not Ready For Data)
NDAC
(Not Data Accepted)
1401.3084.32
active LOW resets the interfaces of the instruments connected to the
default setting.
active LOW signals the transmission of interface messages.
inactive HIGH signals the transmission of device messages.
active LOW enables the connected device to send a service request to
the controller.
active LOW permits switchover to remote control.
has two functions in connection with ATN:
ATN = HIGH
active LOW marks the end of data transmission.
ATN = LOW
active LOW triggers a parallel poll.
active LOW signals a valid data byte on the data bus.
active LOW signals that one of the connected devices is not ready for
data transfer.
active LOW signals that the instrument connected is accepting the
data on the data bus.
8.3
Hardware Interfaces
E-3