MCP3202 only 10bit?

guenthert

I'm using the MCP3202 object from OBEX to read the values from a MCP3202. I find that the lowest two bits are always zero, making it effectively a 10bit ADC. I couldn't see an obvious problem with the software, so I wonder if my chip is broken or I got a fake? Anyone made similar experiences?

Peter Jakacki

Which object? Always best to provide a link to the one you are using or post the code.

kwinn

guenthert wrote: »

I'm using the MCP3202 object from OBEX to read the values from a MCP3202. I find that the lowest two bits are always zero, making it effectively a 10bit ADC. I couldn't see an obvious problem with the software, so I wonder if my chip is broken or I got a fake? Anyone made similar experiences?

It's definitely a 12 bit 2 channel adc, and I have used it a couple of times before standardizing on the 3208. IIRC I used the MCP320x_ez driver.

guenthert

> Which object? Always best to provide a link to the one you are using or post the code.
Right you are. It was just that I downloaded the code a while ago and only recently took this 'project' up again. I just had another look and am able to identify it as http://obex.parallax.com/object/386 . I now see a comment there indicating that it might not work. Hmmh.

Googling, I also found https://github.com/mrmorphic/led-cylinder/blob/master/code/lib/MCP3202.spin , but that looks like it needs more work.

Now I have a few more links I need to digest, but first I need to get lunch ...

guenthert

kwinn wrote: »

[..] IIRC I used the MCP320x_ez driver.

I couldn't find that. I wonder if it got lost (like Pavel's object, see http://forums.parallax.com/discussion/115291/mcp3202-12-bit-adc-converter-c-code-posted-in-obex).

guenthert

Ok, I tried the MCP3202 reader in SPIN (http://obex.parallax.com/object/78) and after some massaging (I don't have an LCD and I intend to use one pin for data in- and output), I got that to work. The chip is fine, all 12bits of it.

This was just a test more or less to satisfy my curiosity, but eventually, I'll have to look more closely, what's wrong with the PASM driver (wonder, whether it might be timing).

kwinn

Sorry about that, I was referring to this one "http://obex.parallax.com/object/315" in my earlier post.

Now using "http://obex.parallax.com/object/371" since settling on the MCP3208. Not much point in stocking multiple adc's since they are only a few cents apart in price.

guenthert

Thanks. Turns out (as you have already guessed, I'm sure) I had a silly bug in my code: I imported the MCP3208 driver object and didn't notice that, as I called the object MCP3202 <facepalm>