DAC0830LCM datasheet(10/28 Pages) NSC

10 / 28 page

DAC0830 Series Application Hints (Continued)

The ILE pin is an active high chip select which can be

decoded from the address bus as a qualifier for the normal

CS signal generated during a write operation. This can be

used to provide a higher degree of decoding unique control

signals for a particular DAC, and thereby create a more

efficient addressing scheme.

Another useful application of the ILE pin of each DAC in a

multiple DAC system is to tie these inputs together and use

this as a control line that can effectively “freeze” the outputs

of all the DAC’s at their present value. Pulling this line low

latches the input register and prevents new data from being

written to the DAC. This can be particularly useful in multi-

processing systems to allow a processor other than the one

controlling the DAC’s to take over control of the data bus and

control lines. If this second system were to use the same

addresses as those decoded for DAC control (but for a

different purpose) the ILE function would prevent the DAC’s

from being erroneously altered.

In a “Stand-Alone” system the control signals are generated

by discrete logic. In this case double-buffering can be con-

trolled by simply taking CS and XFER to a logic “0”, ILE to a

logic “1” and pulling WR

1 low to load data to the input latch.

00560835

*TIE TO LOGIC 1 IF NOT NEEDED (SEE SEC. 1.1).

FIGURE 2. Controlling Mutiple DACs

00560836

FIGURE 3.

DAC0830LCM bảng dữ liệu(PDF) 10 Page - National Semiconductor (TI)