NXPS08P＋DAC输出

anny · 发表于 2019-7-25 13:37:47

本帖最后由 anny 于 2019-7-25 13:55 编辑

S08P芯片没有DAC功能，但是板子上外挂了一个8位的DAC芯片DAC5571，S08P芯片通过IIC与DAC5571通讯。本次实现功能是S08P通过与DAC5571芯片输出电压，然后用S08P芯片的ADC读取出来。

官方已经有了各种测试例程，只要作删减保留自己所要的就能实现功能了。

1、首先还是各种初始化：
Sys_Init();
EnableInterrupts;

printf("\n-- S08-LITE DAC输出实现 --\n");
printf("\n");

//Initialize MTIM0, 625Hz interrupt interval, used for toggle LED
MTIM0_Init();
MTIM0_Start();

//Initialize MTIM1, 1ms interrupt interval, used for 1ms time delay
MTIM1_Init();

//Initialize GPIO used for LED
LED_Init();

//Initialize ADC, 12bit mode
ADC_Init();

//Initialize I2C PTA2/3 used for DAC5571 write/read
DAC5571_Init();

2、本次实验的程序:
      void DAC5571WriteData(unsigned char u8Data)
      {
            /* send data to slave */
            IIC_StartTransmission(DAC5571_I2C_ADDRESS, MWSR);
            i2c_Wait();

            /* Send I2C address */
            I2C_D = u8Data>>4;
            i2c_Wait();

            /* Send data */
            I2C_D = u8Data<<4;
            i2c_Wait();

            i2c_Stop();

            delay();
      }

      void DAC5571_Test(void)
      {
            unsigned short uiADC_Value;
            unsigned long uiADC_Value_temp;

            unsigned char i;
            unsigned char dacOutputValue;
            unsigned char dacOutputValueMin, dacOutputValueMax;
            uint8_t temp;

            //initialize adc channel to measure the dac output
            if (DAC5571_ADC_CHANNEL<8)
            {
                     temp = ADC_APCTL1;
                     temp |= (1<<DAC5571_ADC_CHANNEL);
                     ADC_APCTL1 = temp;
         }
         else
         {
                     temp = ADC_APCTL2;
                     temp |= (1<<(DAC5571_ADC_CHANNEL-8));
                     ADC_APCTL2 = temp;
            }

            printf("DAC5571 test: BEGINS\n");

            while(1)
            {
                     for(dacOutputValue=0; dacOutputValue<255; dacOutputValue++)
                     {
                              DAC5571WriteData(dacOutputValue);
                              DelayMS(1000);

                              uiADC_Value = ADC_GetResult(DAC5571_ADC_CHANNEL);

                              for (i=0; i<10; i++)
                              {
                                    uiADC_Value_temp = ADC_GetResult(DAC5571_ADC_CHANNEL);

                                    uiADC_Value_temp += uiADC_Value;

                                    uiADC_Value = (unsigned short)(uiADC_Value_temp/2);
                              }

                              //8-bit DAC, 12-bit ADC, so the mapping ratio = 4096/256 = 16
                              uiADC_Value = uiADC_Value /16;
                              printf ("输出电压：  %d\n", dacOutputValue);
                              printf ("检测电压：  %d\n", uiADC_Value);
                     }
            }
      }

3、实验结果：

TIM截图20190725133457.png

专用芯片的DAC输出还是很准的！附上点资料，来自于网络

DAC5571 使用心得.rar (398.93 KB, 下载次数: 5)

NXPS08P＋DAC输出

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