Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 335)

15B. Driver488/SUB, W31, W95, & WNT III. COMMAND REFERENCES - 15. Command References
III-320 Personal488 User’s Manual, Rev. 3.0
errorcode=Disarm(ieee,0);
The Disarm command prevents Driver488 from setting the light pen status or invoking an event
handler and interrupting the PC, even when the specified condition occurs. The user’s program can
still check for the condition by using the
Status command. If the Disarm command is invoked
without specifying any conditions, then all conditions are disabled. The Arm command may be used to
re-enable interrupt detection.
DmaChannel
Driver488/SUB and Driver488/W31 only
SYNTAX int pascal DmaChannel(DevHandleT devHandle, int channel);
devHandle refers to either an IEEE 488 interface or an external device. If
devHandle refers to an external device, the DmaChannel command acts on
the hardware interface to which the external device is attached.
channel is the DMA channel to be used by the I/O adapter, or -1 for NONE.
RESPONSE -1 if error
MODE Any
BUS STATES None
SEE ALSO IntLevel, TimeOut
EXAMPLE errorcode = DmaChannel(ieee, 5);
The DmaChannel command specifies which DMA channel, if any, is to be used by the I/O interface
card. The PC has four DMA channels, but channel 0 is used for memory refresh and is not available
for peripheral data transfer. Channel 2 is usually used by the floppy-disk controller and is also
unavailable. Channel 3 is used by the hard disk controller in PCs, but is usually not used in AT
compatible machines. So, channel 1 (and possibly channel 3 ) is available for DMA transfers. The AT
compatible computers have three 16-bit DMA channels: 5 , 6 , and 7 . The MP488CT, MP488, and
AT488 interfaces can use these channels for high speed transfer. The DmaChannel value must match
the hardware jumper settings on the I/O adapter card.
Note: This command is not applicable to the NB488.
Enter (Controller Mode)
EnterX
SYNTAX long pascal EnterX(DevHandleT devHandle, char *data,long
count,bool forceAddr,TermT*term,bool async,int *compStat);
devHandle refers to either an IEEE 488 interface or an external device.
data is a pointer to the buffer into which the data is read.
count is the number of characters to read.
forceAddr is used to specify whether the addressing control bytes are to be
issued for each EnterX command.
term is a pointer to a terminator structure that is used to set up the input
terminators. If term is set to 0 , the default terminator is used.
async is a flag that allows asynchronous data transfer.
compStat is a pointer to an integer containing completion status information.
RETURNS -1 if error,
otherwise, the number of bytes transferred. The memory buffer
pointed to by the data parameter is filled in with the
information read from the device.
MODE CA
BUS STATES ATN
•UNL, MLA, TAG, *ATN, data (With external device handle)
*ATN, data (With interface handle)
SEE ALSO OutputX, Term, EOL, Buffered
EXAMPLE See next page.