National Instruments PC-LPM-16/PnP - Manual (Page 83)

Appendix D Register-Level Programming
 National Instruments Corporation D-11 PC-LPM-16/PnP User Manual
Status Register 1
(Continued)
Bit Name Description
3 EXTINT* External Interrupt Status Bit—This bit reflects the
status of the EXTINT* signal on the I/O connector. If
the EXTINTEN bit in Command Register 1 is set and
this bit is cleared, the external EXTINT* signal has
caused the current interrupt. When the interrupt
caused by the EXTINT* signal is served, your
external device should drive EXTINT* to inactive
state (logic high), or undrive it.
2 CNTINT Counter Interrupt Bit—This bit reflects the interrupt
status caused by the counter 2 output signal. If the
CNTINTEN bit in Command Register 3 is set, a low-
to-high transition on counter 2 output sets this bit and
generates an interrupt request. Clear this bit by writing
to the CNTINTCLR Register.
1 DATAERR
/OVERFLOW Data Error/Overflow Bit—This bit indicates if an
overflow or overrun error has occurred. On the
PC-LPM-16PnP, this bit is the data error bit. If this bit
is cleared, no error was encountered. If this bit is set,
the A/D FIFO has overflowed because the data
acquisition servicing operation could not keep up with
the sampling rate, or an A/D conversion was initiated
before the previous A/D conversion was complete. To
distinguish between the overflow and overrun error
conditions, examine the OVERFLOW and
OVERRUN bits in Status Register 2. Clear this bit by
writing to the A/D Clear Register.
On the PC-LPM-16PnP, this bit only indicates that an
overflow has occurred.
a.Book : l.Appendix D Page 11 Wednesday, November 20, 1996 6:36 PM