da c project

7/27/2019 Da c Project

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AProject Report

onFunction Generator

Using Microcontroller &DAC

Prepared By

Mihir BhavsarRonak Amin

Gaurav Bihola


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Project Report on Function Generator Using Microcontroller & 0808

DACIn the project on Function Generator the Concept we had used is by making the function

Generator using main components as Microcontroller (89c51) & Digital to Analog Converter (0808).

Using this we can generate square wave, triangular wave, sine wave using different programming for eachwaveform in the microcontroller. And can differentiate then with the use of Interrupts.

Block Diagram & Description

The Side shows the Block Diagram of Our

Project. The Digital Data stream ofmicrocontroller Output is applied to the

D-latch (74ls373).This gives the equal delay to the eachdigital data. Now output of the latch is

again in the form of Digital which is

applied to the DAC (0808) that convertsthat digital data in to the analog currentform. Now this current Output data isconverted in to the voltage by the use of

Op-amp (kf 347). So at the output of theOp-amp we get different waves.

Now the thing remain in the project is toprogram the microcontroller for

generating different waveforms.

89C51

80C51 8-bit microcontroller familyThe 89C51/89C52/89C54/89C58 contains a non-volatile FLASH

program memory that is parallel programmable. 89c51 has thesame instruction set as the 80C51.

FEATURES

80C51 Central Processing Unit

On-chip FLASH Program Memory Speed up to 33 MHz Fully static operation RAM expandable externally up to 64 kbytes 4 interrupt priority levels

6 interrupt sources Four 8-bit I/O ports Full-duplex enhanced UARTFraming error detectionAutomatic address recognition

Three 16-bit timers/counters T0, T1 (standard 80C51) andadditional T2 (capture and compare)

Programmable clock out


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Second DPTR register Asynchronous port reset

Low EMI (inhibit ALE) Wake up from power down by an external interrupt

RESET

A reset is accomplished by holding the RST pin high for at least two machine cycles (24 oscillatorperiods), while the oscillator is running. To insure a good power-on reset, the RST pin must be high longenough to allow the oscillator time to start up (normally a few milliseconds) plus two machine cycles. At

power-on, the voltage on VCC and RST must come up at the same time for a proper start-up. Ports 1, 2,and 3 will asynchronously be driven to their reset condition when a voltage above VIH1 (min.) is appliedto RST.

DAC0808

8-Bit D/A ConverterGeneral DescriptionThe DAC0808 is an 8-bit monolithic digital-to-analog converter (DAC) featuring a full scale outputcurrent settling time of 150 ns while dissipating only 33 mW with 5V supplies. No reference current

(IREF) trimming is required for most applications since the full scale output current is typically 1 LSBof 255 IREF/256. The power supply currents of the DAC0808 are independent of bit codes, and exhibits

essentially constant device characteristics over the entire supply voltage range. The DAC0808 willinterface directly with popular TTL, DTL or CMOS logic levels, and is a direct replacement for the

MC1508/MC1408. For higher speed applications.

Features Relative accuracy: 0.19% error maximum

Noninverting digital inputs are TTL and CMOS

Compatible

High speed multiplying input slew rate: 8 mA/s

Power supply voltage range: 4.5V to 18V

Low power consumption: 33 mW @ 5V

Block and Connection Diagrams

Block Diagram Connection Diagram


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Typical Application

Vo = 5V (A1/2+A2/2+A3/2+A4/2+A5/2+A6/2+A7/2+A8/2)

OUTPUT VOLTAGE RANGEThe voltage on pin 4 is restricted to a range of 0.55 to 0.4V when VEE = 5V due to the currentswitching methods employed in the DAC0808. The negative output voltage compliance of the DAC0808is extended to 5V where the negative supply voltage is more negative than 10V. Using a full-scale

current of 1.992 mA and load resistor of 2.5 kW between pin 4 and ground will yield a voltage output of256 levels between 0 and 4.980V. Floating pin 1 does not affect the converter speed or powerdissipation. However, the value of the load resistor determines the switching time due to increasedvoltage swing. Values of RL up to 500W do not significantly affect performance, but a 2.5 kW loadincreases worst-case settling time to 1.2 s (when all bits are switched ON). Refer to the subsequent text

section on Settling Time for more details on output loading.

OUTPUT CURRENT RANGE OF DACThe output current maximum rating of 4.2 mA may be used only for negative supply voltages more

negative than 8V, due to the increased voltage drop across the resistors in the reference currentamplifier.

KF347Features Low input bias current

High input impedance Wide gain bandwidth: 4 MHz Typ. High slew rate: 13 V/s Typ.

Description

The KF347 is a high speed quad JFET input operational amplifier. This feature high input impedance,wide bandwidth, high slew rate, and low input offset voltage and bias current. The KF347 may be used in

circuits requiring high input impedance. High slew rate and wide bandwidth, low input bias current.

Quad Operational Amplifier (JFET)


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Internal Block Diagram

Absolute Maximum Ratings

Parameter Symbol Value UnitSupply Voltage VCC 18 VDifferential Input Voltage VI(DIFF) 30 V

Input Voltage Range VI 15 VPower Dissipation PD 570 mW

Electrical Characteristics(VCC= +15V, VEE= -15V, TA=25 C, unless

otherwise specified)

74LS373Pin Diagram

The SN54/ 74LS373 consist of eight latches with 3-state outputs for

bus organized system applications. The flip-flops appear transparent tothe data (data changes asynchronously) when Latch Enable (LE) is

HIGH. When LE is LOW, the data that meets the setup times islatched. Data appears on the bus When the Output Enable (OE) is

LOW. When OE is HIGH the bus output is in the high impedancestate.

Logic Diagram

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