National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ - Manual (Page 141)

Appendix D Register Map and Descriptions
© National Instruments Corporation D-25 Lab-PC+ User Manual
Counter A1 Data Register
The Counter A1 Data Register is used for loading and reading back contents of
8253(A) Counter 1.
Address: Base address + 15 (hex)
Type: Read-and-write
Word Size: 8-bit
Bit Map:
7 6 5 4 3 2 1 0
D7 D6 D5 D4 D3 D2 D1 D0
Bit Name Description
7-0 D<7..0> 8-bit Counter A1 contents.