Digital-to-Analog Converter (DAC) is a device widely used to convert digital pulses to analog signals. The number of data bit inputs decides the resolution of the DAC since the number of analog output levels is equal to 2”, where n is the number of data bit inputs. Therefore, an 8-input DAC provides 256 discrete voltage (or current) levels of output.

Let’s assume a 8-bit input DAC with reference voltage +5V and full scale output of 10V. Full-scale output of the DAC is achieved when all the data inputs of the DAC are high. The following equation is used to achieve full scale output. V

To generate sine wave, the following table is used to calculate DAC input.

Let’s assume a 8-bit input DAC with reference voltage +5V and full scale output of 10V. Full-scale output of the DAC is achieved when all the data inputs of the DAC are high. The following equation is used to achieve full scale output. V

_{out}= 5V + (5 * sin θ). To find the value sent to the DAC for various angles, we simply multiply the V_{out}voltage by 25.60 because there are 256 steps and full-scale V_{out}is 10 volts. Therefore, 256 steps /10 V = 25.6 steps per volt.To generate sine wave, the following table is used to calculate DAC input.

Angle | Magnitude | Vout | DAC Input |
---|---|---|---|

0° | 0 | 5 | 128 |

30° | 0.5 | 7.5 | 192 |

60° | 0.866 | 9.33 | 238 |

90° | 1.0 | 10 | 255 |

120° | 0.866 | 9.33 | 238 |

150° | 0.5 | 7.5 | 192 |

180° | 0 | 5 | 128 |

210° | -0.5 | 2.5 | 64 |

240° | -0.866 | 0.669 | 17 |

270° | -1.0 | 0 | 0 |

300° | -0.866 | 0.669 | 17 |

330° | -0.5 | 2.5 | 64 |

360° | 0 | 5 | 128 |

```
```
ORG 0H
COUNT EQU 13
AGAIN: MOV DPTR, #TABLE
MOV R2, #COUNT
BACK: CLR A
MOVC A, @A+DPTR
MOV P1, A
INC DPTR
DJNZ R2, BACK
SJMP AGAIN

ORG 300H
TABLE: DB 128, 192, 238, 255, 238, 192
DB 128, 64, 17, 0, 17, 64, 128
END

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