Using LM74 Temperature Sensor with a PIC18F4525

DarrenH · Joined: 25 Jun 2007 Posts: 2

I'm using a National Semiconductor Temperature Sensor LM74 using the Microwire interface to a PIC18F4525, using the following pins:

TEMP_CLK - PIN_E2
TEMP_DATA - PIN_E1
TEMP_CS - PIN_E0

I'd like to read the temperature at regular intervals to control 2 Fans that will run at nominal and high speed. If the temperature is between 40 to 60 degrees C for example, I will run the Fans at 50% duty cycle. If the Temperature is above 60 degrees C, I will run the fans at 80-90% duty cycle. The code for PWM generation of the Fans is working fine.

Does anyone have any working code using the temperature sensor LM74?

Regards,

Darren

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

The LM74 is similar to the Microchip TC77. Here's a software driver
that someone posted. It should get you started.
http://www.ccsinfo.com/forum/viewtopic.php?t=30038&highlight=tc77

DarrenH · Joined: 25 Jun 2007 Posts: 2

Ok thank you, I'll give that a try.

Regards,

Darren