User's Manual

Chapter 4 Register-Level Programming
© National Instruments Corporation 4-11 Lab-NB User Manual
A/D FIFO Register (continued)
Bit Map: Two’s complement binary mode
15 14 13 12 11 10 9 8
Sign Extension Bits D11 D10 D9 D8
76543210
D7 D6 D5 D4 D3 D2 D1 D0
Bit Name Description
15– 0 D<15..0> Data Bit—These bits contain the 16-bit, sign-extended two's
complement result of a 12-bit A/D conversion. Values read,
therefore, range from -2,048 to +2,047 decimal (F800 to 07FF
hex). Two’s complement mode is useful for bipolar analog input
readings because the values read reflect the polarity of the input
signal.