Interface circuit between DAC0832 and 8-bit CPU

The circuit of DAC0832 connected to 8086CPU in single buffer form is shown in Figure 27-13. Since there are 8-bit data inside the DAC0832,
  an interface circuit must be set up between the CPU and the D/A converter to realize data transmission, address selection and read and write control. If there is no input register inside the D/A
chip , an additional circuit is required. Register, starting from the reliability of the system, it is necessary to add a data buffer to the interface. Figure 2 7-14 is the interface circuit
    between DAC0832 and CPU . DO~D7 are 8-bit data lines from the CPU. In order to improve the driving capability of the data bus, DO~D7 must pass through the data line driver Ul (74LS244)t and then be connected to the data input terminals (D10-D17) of DAC0832. WR is The write control line of the CPU; A10~A15 is the address line of the CPU. After being decoded by the U2 (74LS138) 3-8 decoder, the interface address signal is generated. Since the address line AO-A9 does not participate in the decoding, in Figure 27-14 The interface address of DAC0832 is 2000H~23FFH. When D/A conversion is required , the CPU only needs to execute one output instruction to transfer the converted 8-bit data to the data input terminals Dl0-DI7 of DAC0832 through DO~D7 through UI; and immediately start the D/A conversion. , the corresponding analog voltage is output at the op amp output terminal VOUT.