CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to support@ccsinfo.com

I2C temperature sensors

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
Charles Linquist



Joined: 07 May 2005
Posts: 28
Location: Campbell, CA

View user's profile Send private message

I2C temperature sensors
PostPosted: Fri Jun 10, 2005 10:15 pm     Reply with quote

Does anyone know of an I2C temperature sensor that either has more than 3 address bits or else has a programmable address?

I need to hang 20 temp sensors on ONE I2C bus, and I want to keep the hardware at the sensor as minimal as possible.
kender



Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley

View user's profile Send private message Send e-mail Visit poster's website Yahoo Messenger

PostPosted: Sat Jun 11, 2005 10:23 pm     Reply with quote

Hi Charles,

Take a look at MAX6697, although it might have availability problems. It can measure 6 external temperatures and one internal. It doesn't have address pins, but the chip comes in different versions with different hard-wired slave addresses.

You can also multiplex your bus. Arguably, it will still be one I2C bus. Here's one of the app notes about it:
http://www.semiconductors.philips.com/acrobat_download/applicationnotes/AN262_2.pdf

Cheers,
Nick
Charles Linquist



Joined: 07 May 2005
Posts: 28
Location: Campbell, CA

View user's profile Send private message

PostPosted: Sat Jun 11, 2005 11:25 pm     Reply with quote

Since I have to layout a new board for the sensor anyway, I have decided that I'll probably just use a 16F818. It costs less than $2.00. I can use the H/W I2C slave port for the interface to the "main" PIC (18F8722) and either bit-bang an I2C port to talk to a sensor, or use the A/D converter and an analog sensor.

It has enough extra pins to give me access to all 127 I2C addresses.


Charles Linquist
kender



Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley

View user's profile Send private message Send e-mail Visit poster's website Yahoo Messenger

PostPosted: Wed Jun 15, 2005 12:19 am     Reply with quote

Just curious - are you switching to analog temperature sensors?
kender



Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley

View user's profile Send private message Send e-mail Visit poster's website Yahoo Messenger

PostPosted: Wed Jun 15, 2005 12:20 am     Reply with quote

Just curious - are you switching to analog temperature sensors?
Charles Linquist



Joined: 07 May 2005
Posts: 28
Location: Campbell, CA

View user's profile Send private message

PostPosted: Wed Jun 15, 2005 6:33 am     Reply with quote

I have always used analog sensors (LM34), but was thinking of switching to digital so I could get more channels. I really like the analog sensors, since, with averaging, I can get resolution to a tenth of a degree or so.
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group