Agilent Technologies Agilent 34980A, Руководство пользователя

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282 34980A User’s Guide
10
64-Bit Digital I/O Module with Memory and Counter
When set to
ACTive
the interrupt line will be driven by the module.
The high output voltage is set for both the handshaking and interrupt line
on a bank with the
SOURce:DIGital:HANDshake:LEVel
command.
When set to
OCOLlector
the interrupt line will be driven low, but will go
to high impedance mode when in the ‘High’ state. The open collector mode
requires external pull- ups.
The
SENSe:DIGital:INTerrupt:MODE
command sets the condition that will
cause the interrupt to be asserted. When set to
MFULl
the interrupt is
given when the memory is full. When set to
COMPare
the interrupt is
asserted when the pattern is detected (see page page 284 ). When either
condition is removed, the interrupt is de- asserted.
The interrupt line is enabled by the
SENSe:DIGital:INTerrupt:ENABle
command and the status can be checked using the SCPI Status System
(refer to the
Programmer's Reference Help file ).
Byte Ordering
When using buffered memory operations, the width of the data sets how
the memory data is interpreted. Changing the width of the first channel in
a bank invalidates any traces stored or captured.
Output Operations
For output operations (see page 277 ), traces are put
into memory using the
TRACe:DATA:DIGital
command.
For output operations, the data stored in memory is output as follows:
•
BYTE
output - first byte in memory on the first handshake, next byte in
memory on the second handshake, and so on.
•
WORD
output - first and second byte in memory on the first handshake,
next two bytes in memory on the second handshake, and so on.
•
LWORd
output - first four bytes in memory on the first handshake, next
four bytes in memory on the second handshake, and so on.
Note that for
WORD
outputs the first byte in memory is considered the
most significant byte and is output on the upper bits (8 through 15).
For
LWORd
outputs the first byte is output on bits 24 through 31.
You can change the byte order reported using the
FORMat:BORDer
command. This command allows you to swap the most- significant and
least- significant byte ordering for all data transfer operations.
The command is applied globally and cannot be assigned to an individual
slot or channel.