Chapter 3
Register Map and Descriptions
3-18
©
National Instruments Corporation
DAC FIFO Data Register
The DAC FIFO Data Register is used to load the desired data into the DAC data FIFO.
The DAC FIFO is 2 kwords deep on the PCI-MIO-16E-1, PCI-MIO-16XE-10, PCI-6031E,
and PCI-6071E. The DAC FIFO is 512 words deep on the PCI-MIO-16E-4. The DAC FIFO
is 0 words deep on the PCI-MIO-16XE-50. The empty, half-full, and full flags from the 2
kword and 512 word DAC data FIFO are available in a status register in the DAQ-STC. These
flags indicate when the FIFO is empty, half-full, or full, respectively. Only the full flag is
available on the boards with the 0 word deep DAC data virtual FIFO. Whenever the FIFO is
not full the host is free to write additional data.
Address:
Base a 1E (hex)
Type:
Write-only
Word Size:
16-bit
Bit Map:
Bit
Name
Description
15–0
D<15..0>
Data bits 15 through 0—The data to be written to the DAC
data FIFO. This data is interpreted in straight binary form
when DAC is configured for unipolar operation. In
unipolar mode, the valid range is 0 to 65,536 for a 16-bit
DAC and 0 to 4,096 for a 12-bit DAC. When the DAC is
configured for bipolar operation, the data is interpreted in
two’s complement form. In bipolar mode, the valid range
is –32,768 to 32,767 for a 16-bit DAC and –2,048 to 2,047
for a 12-bit DAC.
15
14
13
12
11
10
9
8
D15
D14
D13
D12
D11
D10
D9
D8
7
6
5
4
3
2
1
0
D7
D6
D5
D4
D3
D2
D1
D0