HP 3455A Operating And Service Manual page 32

Section LEI
Address 3455A Program
Command Information
ete ee OC
wit 722, "Fl R3 A@ HI M3 T3"
3455A listen
address
output to the
(decimal equivalent)
bus, includes
the unlisten command
and calculator talk
address
Program data message using the 9825A Calculator.
3-64. Entering MATH Constants (¥-and Z) from the Bus. The
following data message illustrates the program informa-
tion necessary to enter numbers into the Y and Z
registers:
Address Program
Command Information
ane ge
(refer to Controller
"EY 123.456 SY EZ 45.6789 SZ"
Manual)
Enters number
in "Z" Register
Programs the
3455A to store
the displayed
number in the
"Y" Register.
Number to
be entered
Programs the
3455A to enter
numerical data
into the display
addresses controller to
"talk" and 3455A to "listen"
The number stored in the Y or Z register can be read
from the Bus by programming the ENTER feature and
the particular register. This transfers the number from
the storage register specified to the display. The number
displayed is output to the Bus by addressing the 3455A
to 'talk'?. The number is returned to the storage
register by programming the STORE feature and the
desired register. The following example illustrates how
to read the numbers stored in the Y and Z register from
the Bus:
Address
Command
wrt 722 , "EY"
Addresses the Transfers the number
controller (9825A) stored in the Y register
to "talk" and the
3455A to "listen"
3-10
into the 3455A display
Model 3455A
ted 722, A ;dspA
Outputs the contents of
the controller's "A" register
to the display
Addresses
the 3455A
to "talk" and
(9825) to controller register
listen
to receive the
number
wrt 722 , "SY"
Returns the number in
the 3455A display to the Y
register
Addresses the
controller (9825A) to
"talk" and the 3455A
to "listen"
3-65. Data Ready Request. The DATA READY Request
feature permits the 3455A to signal the controller upon
the completion of a measurement. This feature would
normally be used where the 3455A is triggered from an
external source. In this mode of operation, the 3455A is
programmed to the appropriate measurement
parameters (FUNCTION, RANGE, etc.). The con-
troller is then free to control other instruments on the
Bus. Upon being triggered, the 3455A makes a measure-
ment and outputs a ''Require Service'? message to
notify the controller that the measurement information
information is ready. Upon receiving the service re-
quest, the controller with serial poll the 3455A to deter-
mine the nature of the service request. Upon being poll-
ed, the 3455A outputs a status byte, in this case the
ASCII character ''A'' (decimal 65), indicating the
measurement data is ready. The controller then disables
the serial poll and reads the measurement data. The pro-
gram codes for the DATA READY RQS feature are: _
D@ Data Ready Request off
D1 Data Ready Request on
3-66. Binary Program Feature. The BINARY PROGRAM
feature permits the status of the FUNCTION, RANGE,
TRIGGER, MATH, AUTO-CAL and HIGH RESO-
LUTION controls to be determined or programmed
from the bus in four 8-bit binary words. The BINARY
PROGRAM feature allows faster programming of the
3455A by reducing the number of program data bytes
from a maximum of 12 for normal programming to 4
data bytes for binary programming. The BINARY
PROGRAM codes can also be read and stored by the
controller to re-program the 3455A at a later time (see
Appendix A). One important thing to remember is to
send a ''B'' to the 3455A in order to put the instrument
into the BINARY mode. Table 3-5 lists the allowable
BINARY PROGRAM codes for each of the four data
bytes and the front panel keys they control.