Design of D/A triangle wave generator based on single chip microcomputer

D/A Converter

• When CS=0 and ILE=1, the signal on the data bus is written into the 8-bit input latch when the WR1 signal is valid.

• When XFER=0, the data of the input register is transferred to the 8-bit DAC register when the WR2 signal is valid, and the output value changes accordingly

Way of working:

• Direct working mode (as shown in the following experiment)

• When a ground line or the output line of the address decoder makes CS valid (low level), ILE high level, and WR1/XFER/WR2 is low level, the data byte on the microcontroller data line passes directly through the D/A converter, is converted and output

• CS and WR1 are connected to the pins and set to low level by software

• VCC, VREF, ILE connect to POWER

• WR2, XFER, RFB, GND*2 to GND

• Single buffer mode

  

• Only applicable to systems with only one analog output or several analog outputs but no synchronization is required

• ILE, VCC to POWER

• CS and XFER are connected to the microcontroller pins, and the input register and DAC register addresses are both 7FFFH

• WR1 and WR2 are connected to the MCU WR pin, and the MCU write signal

• When the microcontroller performs a write operation on DAC0832, a byte of data is directly written into the DAC register, and the output analog value changes accordingly.

• Double buffering

  

• When multiple D/A conversion interfaces require synchronous D/A conversion output, double buffering must be used. The input latching and D/A conversion output of DAC0832 digital quantity are completed in two steps. That is, the CPU data bus outputs digital quantity in time-sharing and latches it in the input register of each D/A converter; then the CPU sends a control signal to all D/A converters, and each input register → DAC register realizes synchronous conversion output.

• Each analog output requires a DAC0832

• The output latch address of DAC0832 (1) is 0DFFFH

  DAC0832 (2) output latch address 0BFFFH

  The DAC register address of the two DAC0832s is the same as 7FFFH

————————————————————————————————————————————

Triangle wave generator experiment based on DAC0832

Experimental description:

• Use the DAC0832 chip to make a signal generator and output a triangle wave signal

• Direct working mode

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Wiring Instructions:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Implementation code:

include

typedef unsigned char uchar;

typedef unsigned int uint;

sbit cs = P3 ^ 7;

sbit wr = P3^6;

void Delay(uchar m)

{

    while(m--);

}

void main()

{

    uchar k = 0; //Set the initial value of k to 0

    cs = 0; //When CS and WR1 are set to low level, be ready to write data. As long as there is data output from P0 port, DAC0832 will convert it into analog signal

    wr = 0;

    while(1) //The output value changes between 0-255 and 255-0, and the analog signal can be seen through the oscilloscope

    {

        while(1) //The output value changes between 0-255

        {

            P0 = k++; //output k and k+1

            Delay(1);

            if (k == 0xff) //End the loop when it reaches 255

                break;

        }

        while(1) //The output value changes between 255-0

        {

            P0 = k--; //Output k and k-1

            Delay(1);

            if (k == 0x00) //End the loop when it reaches 0

                break;

        }

    }

}