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5500A
Operator Manual
5-55. Programming the ISR, ISCR, and ISCE
To read the contents of the ISR, send the remote command, ISR?. To read the contents
of the ISCR0 or 1, send the remote command, ISCR0?, or ISCR1?. To read the
contents of the ISCE0 or 1, send the remote command, ISCE0?, or ISCE1?. The
5500A Calibrator responds by sending a decimal number that represents bits 0 through
15. Every time you read the ISCR0 or 1, its contents are zeroed. The following sample
program reads all five registers:
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! THIS PROGRAM READS THE ISR, ISCR, AND ISCE REGISTERS
! NOTE THAT THE ICSR? COMMANDS CLEAR THE ISCR CONTENTS
PRINT @6, "ISR?"
! ASK ISR CONTENTS
INPUT @6,A%
! RETRIEVE REGISTER CONTENTS FROM 5500A
PRINT @6, "ISCR0?"
! ASK FOR AND CLEAR ISCR0 CONTENTS
INPUT @6, B%
! RETRIEVE REGISTER CONTENTS FROM 5500A
PRINT @6, "ISCE0?"
! ASK FOR ISCE0 CONTENTS
INPUT @6, C%
! RETRIEVE REGISTER CONTENTS FROM 5500A
PRINT @6, "ISCR1?"
! ASK FOR AND CLEAR ISCR1 CONTENTS
INPUT @6, D%
! RETRIEVE REGISTER CONTENTS FROM 5500A
PRINT @6, "ISCE1?"
! ASK FOR ISCE1 CONTENTS
INPUT @6, E%
! RETRIEVE REGISTER CONTENTS FROM 5500A
PRINT "ISR = ";A%
! DISPLAY ISR
PRINT "ISCR0 = ";B% ! DISPLAY ISCR0
PRINT "ISCE0 = ";C% ! DISPLAY ISCE0
PRINT "ISCR1 = ";D% ! DISPLAY ISCR1
PRINT "ISCE1 = ";E% ! DISPLAY ISCE1
END
Convert the returned variables into binary, and you can read the status of the instrument.
For example if a register contains 4, its binary equivalent is: 00000000 00000100.
Therefore, bit 3 (VBOOST) is set (1) and the rest of the bits are reset (0).
By setting the bits in an ISCE register, you can mask (disable) the associated bits in the
ISCR. For example, to cause an SRQ interrupt when the output has settled, bit 12
(SETTLED) in the ISCE1 register must be 1. (The ISCB bit must also be enabled in the
SRE.) The following sample program loads a decimal 1024 into the ISCE, which sets bit
12 and resets the other bits:
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! THIS PROGRAM LOADS 00010000 00000000 BINARY INTO THE ISCE
PRINT @6, "ISCE 4096" ! LOAD DECIMAL 4096 INTO ISCE
PRINT @6, "ISCE?"
! READ BACK ISCE VALUE
INPUT @6, A%
! "
PRINT "ISCE = ";A%
! PRINT IT, IT SHOULD BE 4096
END
5-56. Output Queue
The output queue is loaded whenever a query is processed, and holds up to 800
characters. The controller reads it with a statement such as a BASIC INPUT statement,
removing what it reads form the queue. If the queue is empty, the 5500A Calibrator does
not respond to the INPUT statement from the controller. The Message Available (MAV)
bit in the Serial Poll Status Byte is 1 if there is something in the output queue and 0 if the
output queue is empty.
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