Keithley 486 Instruction Manual page 215

APPEh'DIXD
Controller Programs
IBM PC/XT/AT with Capital Equipment Corporation PC<>488 Interface
(Keithley PC-488.CEC)
Introduction
General information about controlling a Model 486/487
with an IBM PC/XT/AT computer and Capital Equip-
ment CorporationPCcrl88 interface is given here. Refer
to the CEC PC0488 Programming and Reference Man-
ual for complete informalion.
Initializing the System
Thefirststepinsnyprogramistoinitializethesystemus-
ing the m routine. This routine sets the pri-
mary IEEE-488 bus address of the PCo488, specifies the
type of controller to be used, and sends an interface clear
(EC) to the other devices on the bus.
After booting up the IBM using DOS and entering
BASICA, the statements of program 1 can be used at the
start of any program to initialize the system:
Line 30 sets the address of the PC0488 to 21, however,
any other valid address could be used as long as it does
not
conflict
with the address of any other device on the
bus.
Interface Basic Programming Statements
This paragraph covers the PC<- statements that are
essential to Model 486/487 operation. A partial list of
programming statements is contained in Table D-l. The
IBM BASIC CALL statement is used to execute the de-
sired action. Before a CALL routine can be used, BASIC
needs to know the offset address of the routine. In the ta-
ble, the first statement of each programming sequence
defines the offset address of the CALL routine.
Example Program
The following program sends a command siring from an
IBMPC/XT/ATcomputertotheMode1486/487anddis-
plays the response on the CRT. The computer must be
equipped with a CEC interface card and DOS 2.0 (or later
revision) operating system.
Directions
1.
2.
3.
4.
5.
Using the front panel MENU key, set the primary
IEEE-488 address of the Model 486/487 to 22.
With the power off, connect the Model 486/487 to
the IEEE-488 interface card installed in the IBM com-
puter.
Type in BASICA on the computer keyboard to get
into interpretive BASIC lsnguage.
Enter the lines of Program 2 using the return key af-
ter each line. -
Run the program and type in the desired command
stringattheENTERCOMMAN0 STRING? prompt
For example, to view the instrument modelnumber
and firmware revision, type in U2X and press the re-
turn key. The Model 4861487 firmware revision will
then appear on the computer display. A single read-
ing will appear for DDCs that have no response.
PROGRAM COMMENTS
10 DEF SEG=&HC400 ' Memory offset.
20 -=o
' Offset address of routine
30 MY.ADDRESS%=Zl ' Set PC<w@t? address.
40 CONTROLLER%=0 ' Set for system control.
50 CALL wrru.~IzE (~.ADDREsS%, ' Execute lNlTIALIZE routine.
CONTROLLER%)
Program 1
D-2