96-Bit Parallel Digital I/O Interface User Manual

Chapter 5 Register Map and Description
© National Instruments Corporation 5-5 PCI-DIO-96 User Manual
Table 5-2 shows the control words for setting or resetting each bit in
port C. Notice that bit 7 of the control word is cleared when
programming the set/reset option for the bits of port C.
Register Description for the 82C53
Figure 5-2 shows the control word format used to completely program
the 82C53. Bits 7 and 6 of the control word select the counter to be
programmed. Bits 5 and 4 select the mode by which the count data is
written to and read from the selected counter. Bits 3, 2, and 1 select the
mode for the selected counter. Bit 0 selects whether the counter counts
in binary or BCD format.
Table 5-2. Port C Set/Reset Control Words
Bit Number Bit Set
Control Word
Bit Reset
Control Word
Bit Set or Reset
in Port C
0 0xxx0001 0xxx0000 xxxxxxxb
1 0xxx0011 0xxx0010 xxxxxxbx
2 0xxx0101 0xxx0100 xxxxxbxx
3 0xxx0111 0xxx0110 xxxxbxxx
4 0xxx1001 0xxx1000 xxxbxxxx
5 0xxx1011 0xxx1010 xxbxxxxx
6 0xxx1101 0xxx1100 xbxxxxxx
7 0xxx1111 0xxx1110 bxxxxxxx