Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 71)

8E. Microsoft C II. SOFTWARE GUIDES - 8. Driver488/DRV
II-56 Personal488 User’s Manual, Rev. 3.0
All the commands discussed so far: OPEN , RAWMODE , IOCTL_WT , RESET , EOL OUT , EOL IN and FILL
ERROR are part of the IEEEINIT function included in IEEEIO.C . IEEEINIT returns a zero if these
steps were executed successfully, and a -1 if some error was encountered. Thus, to accomplish all the
above steps, we just use the following:
#include “ieeeio.h”
#include
if (ieeeinit() == -1) {
printf(“Cannot initialize IEEE system.\n”);
exit(1);
}
The two INCLUDE statements provide the program with definitions of the standard I/O and IEEE I/O
functions so they can be referenced by the demo program. IEEEINIT is called to initialize the system,
and if it indicates an error (returns a -1 ), we print an error message and exit. If there was no error, we
just continue with the program.
Once everything is reset, we can test the communications and read the Driver488/DRV revision number
with the
HELLO command:
char response[256];
ieeewt(“hello\n”);
ieeerd(response);
printf(“%s\n”,response);
We first IEEEWT the HELLO command, then IEEERD the response from Driver488/DRV into the
character string response ( IEEEWT and IEEERD are both supplied in IEEEIO.C ). Finally, we display
the response with a PRINTF .
It is not necessary to perform the HELLO command, but it is included here as a simple example of
normal communication with Driver488/DRV. Its response is the revision identification of the
Driver488/DRV software:
Driver488 Revision X.X ©199X IOtech, Inc.
We can also interrogate Driver488/DRV for its status:
ieeewt(“status\n”);
ieeerd(response);
printf(“%s\n”,response);
Subsequently, the printed response is similar to the following:
CS21 1 I000 000 T0 C0 P0 OK
The following indicators describe each component of the Driver488/DRV status:
Indicator Driver488/DRV Status
C It is in the Controller state.
S It is the System Controller.
21 The value of its IEEE 488 bus address.
1 An Address Change has occurred.
I It is idle (neither a talker nor a listener).
0 There is no ByteIn available.
0 It is not ready to send a ByteOut .
0 Service Request ( SRQ ) is not asserted.
000 There is no outstanding error.
T0 It has not received a bus device TRIGGER command (only applicable in the Peripheral
mode).
C0 It has not received a CLEAR command (only applicable in the Peripheral mode).
P0 No CONTINUE transfer is in progress.
OK The error message is “OK”.