Register Descriptions - National Instruments PC-LPM-16/PnP User Manual

Appendix D Register-Level Programming
Register Name
Counter/Timer (MSM82C53)
Register Group
Counter 0 Data Register
Counter 1 Data Register
Counter 2 Data Register
Counter Mode Register
Timer Interrupt Clear Register
Digital I/O Register Group
Digital Output Register
Digital Input Register
*PC-LPM-16PnP only.
Register Size

Register Descriptions

PC-LPM-16/PnP User Manual
Table D-1. PC-LPM-16/PnP Register Map (Continued)
The PC-LPM-16/PnP registers are 8-bit registers. To transfer 16-bit
data, you need two consecutive I/O read or write operations. For
example, to read the 16-bit A/D conversion result, read the low byte of
FIFO first, then the high byte of FIFO.
Table D-1 divides the PC-LPM-16/PnP registers into four different
register groups. A bit description of each of the registers making up
these groups is included later in this appendix.
The Configuration and Status Register Group controls the overall
operation of the PC-LPM-16/PnP and the D/A circuitry. The Analog
Input Register Group reads output from the successive-approximation
ADC. The Counter/Timer Register Group accesses the onboard
MSM82C53 counter/timer integrated circuit. The Digital I/O Register
Group consists of the digital output and input registers.
Offset Address
(Hex)
8 Read-and-write
9 Read-and-write
A Read-and-write
B Write-only
6 Write-only
4 Write-only
5 Read-only
D-2
Type Size
8-bit
8-bit
8-bit
8-bit
8-bit
8-bit
8-bit
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