This document discusses interfacing digital-to-analog converters (DACs) and sensors with PIC microcontrollers. It introduces DACs and common DAC types like R-2R ladder and weighted resistor DACs. It then discusses interfacing a DAC0808 converter to a PIC microcontroller and sensing light intensity with an LDR light sensor. Finally, it describes interfacing the LM75 temperature sensor to a PIC, including the sensor's register structure and digital output representation of temperature readings.

1. SASIDHARAN.S
DEPARTMENT OF EEE
DAC and Sensor Interfacing with
PIC Microcontroller

2. AGENDA
 INTRODUCTION OF DAC
 TYPES OF DAC
 DAC CONVERTER (DAC 0808)
 INTERFACING DAC TO PIC
 INTRODUCTION ABOUT SENSORS
 SENSOR INTERFACING WITH PIC
 LDR AND LM75
 CONCLUSION

3. INTRODUCTION TO DAC
 The DAC is widely used to convert digital pulses into
analog signals

4. PARAMETERS OF DAC
 RESOLUTION
It is defined as the smallest change that can occur in analog
output as a result of change in the digital output
 FULL SCALE OUTPUT
The maximum output available from a DAC ( all binary
inputs are one)
 MONOTONICITY
A DAC is said to be Monotonic if its output increases as the
binary input is incremented from one value to the next

5. TYPES OF DAC
 R-2R LADDER TYPE DAC

6. TYPES OF DAC
 WEIGHTED RESISTOR TYPE DAC

7. PIC CONNECTION TO DAC 0808
𝐼 𝑂𝑈𝑇 = 𝐼 𝑅𝑒𝑓
𝐷7
2
+
𝐷6
4
+
𝐷5
8
+
𝐷4
16
+
𝐷3
32
+
𝐷2
64
+
𝐷1
128
+
𝐷0
256
+

8. DAC OUTPUT (INTERFACING OF DAC TO PIC)
 Two DAC Output s are easily added to a PIC with
MAX 518 (8pin DIP)

9. INTRODUCTION
 Whether or not the Embedded Microcontroller is a
Human Interface, it will certainly interface with the
physical world.
 Output Transducers converts electrical variables to
physical.
 Some simple sensors, The Micro switch

10. LDR INTERFACING WITH PIC
(1) LDR:
 Sensitivity depends on
intensity of light.
 Resistance of LDR
decrease with increase
in intensity of light and
vice-versa.

11. LDR INDICATIVE OUTPUT VALUES
ILLUMINATION
(Lux)
R LDR
ohms
Vo
Volts
DARK 2M 5.00
10 9k 2.36
1000 400 0.19

12. NTERFACING A TEMPERATURE SENSOR
 National Semiconductor’s LM75 combines an
analog temperature transducer, an analog to
Digital Converter(9 bit) and an I2C bus interface
 Temperature range covered -25 to 100 C

13. REPRESENTATION OF DIGITAL OUTPUT
CORRESPONDING TO TEMPERATURE

14. DEFAULT PERFORMANCE OF THE O.S (OVER TEMPERATURE-
SHUTDOWN) OUTPUT

15. REGISTER STRUCTURE OF LM75

16. You can download this PPT from the
Website: sasidharansrinivasan0197.blogspot.in