Address decoding interface circuit

Decoding circuit: In order to make each interface work properly, the system needs to allocate addresses to all ports. According to the number of interfaces in the system
, 16 addresses can be translated using 74LS154. The interface circuit is shown in Figure 27-50.
    In the figure, address buses A15 and A14 control the control terminal Gl of the decoder. A13 and A12 control the control terminal G2 of the decoder. All—A8
is connected to the decoder selection control terminals D, C, B, and A. From this, each port address can be analyzed, see Table 27-2.
  In addition, this system is also equipped with 8 D/A conversion circuits, which convert the control quantities output by the processor to each channel into analog quantities and send them to
the corresponding actuators. Using DAC0832, the output is 4-20mA.