National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ - Manual (Page 154)

Register Map and Descriptions Appendix D
Lab-PC+ User Manual D-38 © National Instruments Corporation
Interval Counter Register Group
The 8-bit Interval Counter is used only in the single-channel interval mode (SCANEN = 0 and
INTSCAN = 1) and consists of two 8-bit registers–the Interval Counter Data Register and the
Interval Counter Strobe Register. The Interval Counter Data Register is loaded with the count.
Writing to the Interval Counter Strobe Register loads this count into the Interval Counter. The
Interval Counter decrements with each conversion. When the count reaches 0, the Interval
Counter autoinitializes, restoring the original count value.
Bit descriptions for the registers in the Interval Counter Register Group are given on the
following pages.