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2.6.1. Simple Experiment to Generate a Voltage
from DAC
In this lesson we are like to design, how to generate
a voltage 2 volt from DAC0808. There is something you must to do is
to calculate the konstanta K, as you have learned in previous lesson.
Step 1st
Build the circuit as shown in figure 2.6.2 As you seen on figure 2.6.2.
P0.0 trough P0.7 is connected to A8 - A1.
or example, we assumes that the Vref = 5 volt, R14 = 5 k, and Rf = 5k
K = Vref/ R14;
= 5/5k
= 1 mA
If, we put logic high into A1 through A8 then we have:
Io = 1 mA x 0.99
= 1 mA
So,Vo = Io x Rf
= 1 mA x 5k
= 5 volt
Voltage Resolution = 5/255 = 0.02 volt
If you like to send a 2 volt out from your DAC, than you
must write down this decimal
= 2/0.02
= 100 decimal
Step 2nd
In this step, you must tipe the assembly program to make a voltage from
your DAC, we assume that you have already known the editor, we used
MIDE-51 to edit the program. ( Download Complete
Circuit File : DAC0808.pdf )
org 0h
start: mov A,#100
mov P0,A
sjmp start
Step 3rd
Safe your assembly program above, and name it with dac1.asm (for example)
Compile the program that you have been save by using MIDE-51, see the
software instruction.
Step 4th
Download your hex file ( dac1.hex ) into the microcontroller
by using Microcontroller ATMEL ISP software, see the instruction.After
download this hex file you'll see the action of DAC ( of course if your
cable connection and your program are corrected )
Comments,
questions and discussion about this topic
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