[SOLVED] DS18B20 temperature correct reading only in debug mode, not with production firmware

Status
Not open for further replies.
D

Drugo

Junior Member level 2
Joined
Feb 23, 2011
Messages
20
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Visit site
Activity points
1,537
Hello, I am experiencing a weird behavior with temperature readings from a DS18B20 Dallas temperature sensor. I am using a dsPIC33, ICD3 for debugging/downloading the firmware, XC16 compiler and I display the temperature on the console through serial port.
The problem is that I perfectly read the temperature in debug mode, while, in production mode, I read Temperature LSB and Temperature MSB of the scratchpad always equal to zero. :bang:

I am in big trouble because I have to deliver the firmware for the production next Tuesday. Could anyone please help me to fix this issue?

Thanks a lot in advance :thumbsup:
 
Last edited:

post your code here.what is the bit resolution you set?
 

I got the final answer from the Microchip forum and want to post it for completeness. I am using AN5/IC8/CN7/RB5 pin to receive the digital data from the Dallas DS18B20 temperature sensor. In the inherited code I'm working on this pin was used as an analog one because the previous temperature sensor was analog. So, when it was analog, I found this initialization:

AD1PCFGLbits.PCFG5 = 1;

that I changed as digital in this way:

AD1PCFGLbits.PCFG5 = 0;

The mistake was that the initialization of this pin (as digital, in my current case) has to be:

AD2PCFGLbits.PCFG5 = 1;

In debug mode, as reported at page 20 of dsPIC33FJ128GP706A datasheet, all AN pins are configured by default as digital. So that's the reason why it worked in debug mode and not in production one.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…