Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 357)

15B. Driver488/SUB, W31, W95, & WNT III. COMMAND REFERENCES - 15. Command References
III-342 Personal488 User’s Manual, Rev. 3.0
SEE ALSO PPoll, PPollUnconfig, PPollDisable
EXAMPLE errorcode =
PPollConfig
(dmm,0x0D);
Configure device DMM to assert DIO6 when it desires service (ist
= 1) and it is Parallel Polled (0x0D = &H0D = 1101 binary;
S=1, P2=1, P1=0, P0=1; 101 binary = 5 decimal = DIO6).
The PPollConfig command configures the Parallel Poll response of a specified bus device. Not all
devices support Parallel Polling and, among those that do, not all support the software control of their
Parallel Poll response. Some devices are configured by internal switches.
The Parallel Poll response is set by a four-bit binary number response: S , P2 , P1 , and P0 . The most
significant bit of response is the Sense ( S ) bit. The Sense bit is used to determine when the device will
assert its Parallel Poll response. Each bus device has an internal individual status ( ist ). The Parallel
Poll response is asserted when this ist equals the Sense bit value S . The ist is normally a logic 1
when the device requires attention, so the S bit should normally also be a logic 1 . If the S bit is 0 , then
the device asserts its Parallel Poll response when its ist is a logic 0 . That is, it does not require
attention. However, the meaning of ist can vary between devices, so refer to your IEEE 488 bus
device documentation. The remaining 3 bits of response: P2 , P1 , and P0 , specify which DIO bus data
line is asserted by the device in response to a Parallel Poll. These bits form a binary number with a
decimal value from
0 through 7 , specifying data lines DIO1 through DIO8 , respectively.
PPollDisable
SYNTAX int pascal PPollDisable(DevHandleT devHandle);
devHandle is either an interface or an external device that is to have its Parallel
Poll response disabled.
RETURNS -1 if error
MODE CA
BUS STATES ATN
•UNL, MTA, LAG, PPC, PPD
SEE ALSO PPoll, PPollConfig, PPollUnconfig
EXAMPLE errorcode = PPollDisable(dmm); Disable Parallel Poll of device DMM.
The PPollDisable command disables the Parallel Poll response of a selected bus device.
PPollDisableList
SYNTAX int pascal PPollDisableList(DevHandlePT devHandles);
devHandles is a pointer to a list of external devices that are to have their Parallel
Poll response disabled.
RETURNS -1 if error
MODE CA
BUS STATES ATN
•UNL, MTA, LAG, PPC, PPD
SEE ALSO PPoll, PPollConfig, PPollUnconfig
EXAMPLE deviceList[0] = wave;
deviceList[1] = timer;
deviceList[2] = dmm;
deviceList[3] = NODEVICE;
errorcode = PPollDisableList(deviceList);
The PPollDisableList command disables the Parallel Poll response of selected bus devices.
PPollUnconfig
SYNTAX int pascal PPollUnconfig(DevHandleT devHandle);
devHandle refers to a hardware interface. If devHandle refers to an external
device, then the PPollUnconfig command acts on the hardware interface to
which the external device is attached.
RETURNS -1 if error