ADC on 18F452

0mega said:

Hello All,

I want to use a PIC 18F452 to do analogue to digital conversion. I know how to aquire the input using C18 or assembly, but i am not sure how to wire it up. My input voltage will be around 20VDC +- 4V, however i intend to use this through a voltage divider, so i'll convert to 2.0VDC +- 0.4V (ie. 1/10).

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What would i wire to vref? I read at
that a TL341 chip (what is that?) will give 2.5V range.... this is perfect.

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How would i wire up such a circuit?

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0mega said:

Soz, Your website was down, so i couldn't dl the schematic, i have done so now. Thankz a dozen.

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(How about making a usb board?? Look at PicNet USB)

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Nigel Goodwin said:

As you've already seen my tutorial, you will have noticed that I use an opamp fed from a potential divider (to give 10V range), all you would need to change is the input resistor to give 20V range.



As the tutorial mentions, the TL341 is a precision voltage reference source, there are various different ones available - but they usually end in 341. The one I used actually came from an old VCR, they are commonly used in switchmode power supplies for the regulation - a lot of TV's and VCR's have them.



Wire it like my tutorial, I'm not sure which pins the 18F452 uses, so you will need to check the datasheet - presumably, like the 16F876, you will need to configure the chip correctly - the details in my tutorial should help you work it out.

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rashidme said:

Hello,

I really like your tutorials and i was wondering if i can use your code on a 18F4520. I have a pic Dem 2 board from microchip.

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