walang ADC ang 16F628A. use a f88 or F887a (same cost @ egizmo)
pahabol...sa Vref kailangan mo lagyan nang potentimeter para sa calibration nang lm35. para di ka na gumamit nang opamp for amplifiying the signal.
hindi po kasi ako familiar kung paano magprogram ng ibang microcontroller aside from 16f84a pero willing po akong matuto..hehehe..pareho lang po ba ang approach ng pagprogram 16f88, 16f77a at 16f84a..?(mplab ide po ang gamit namin sa skul sa pagprogram sa 16f84a)
^ it's more involved with the resolution rather than compensating the voltage drop.if may error i'll stand corrected... medyo di ako magaling dito.. gamitin natin yung figure 1 from the datasheet. FIGURE 1. Basic Centigrade Temperature Sensor(+2°C to +150°C)Linear + 10.0 mV/°C scale factorand lets try to get a 8 bit value from the adc. for simplicity... factors to consider first...*0-255 ang dec variable from boostC*assume that you'll measure only 0°C to 150°Cif you have a same Vref with the Vdd rail (5+)now... 150°C * 10mv = 1500mv or 1.5volts... or 75 decimal... di mo makukuha yung fullrange nang ADC mo na 255...you're losing so much!0.5°C accuracy guarantee-able (at +25°C)by lowering Vref to 1.5 volts...150°C * 10mv = 1500mv or 1.5volts... or 255 decimal 8bit you have the full range 0°C @ 0mV and 150°C @ 255or in 10bit 150°C @ 1025 dec. (it won't be linear anymore. it's more on the ADC side not THE LM35... that's where a lookup table and calibration data works.) konti lang naman... ibang topic na
Yung ATmel AVR's meron ding adc pero meron siyang pins for avcc at vref para sa adc. So you could chose your reference voltage sa adc. Hindi ko pa po natry hanggang pic adc palang ako.
