Measurement Computing Analyzer488 - Manual (Page 52)

Section 3 Front Panel Operation
3.6
DAV The DAV LED indicates the state of the Data Valid (DAV)
handshaking line. The LED is on when the DAV line is
asserted. This LED indicates the real-time state of the bus,
even when viewing recorded data.
3.5.3 Bus Display Mode
Bus display mode is the default display mode of the Analyzer488.
In normal operation, with the BUS LED on, the -LOCATION- area of
the front panel display shows the word:
BUS , followed by bus data in
the -MESSAGE- area of the display. When recording events (RECORD
LED is on), -LOCATION- shows the next record memory location that
will be used to record bus events. The -MESSAGE- area still shows
the actual state of the bus data lines.
When the Analyzer488 is in the Talk state (TALK LED is on), the
actual state of the data lines shown in the -MESSAGE- area may not
be the same as the driven state, shown by the keyboard LED indicators.
If the actual state of the data lines is different from the driven state, the
bus data in the -MESSAGE- area will flash. If hexadecimal format is
used, the hexadecimal value will flash. If binary format is used, the
digits that represent the individual lines that are different will flash.
3.5.4 Memory View Mode
Memory view mode is used to examine record memory. In
normal operation, with the MEMORY LED on, the -LOCATION- area
shows a record memory location address and corresponding bus data in
the -MESSAGE- area. When recording events (RECORD LED is on), -
LOCATION-
does not change, recording goes on in the background. If
the current memory location is overwritten, the -MESSAGE- area will
change to show the new bus event that was recorded into the location.
3.6 Keyboard
The front panel keyboard contains 46 pushbutton keys and 14 LED
indicators. Command keys provide immediate actions, menu keys give menu