Interfacing a Picmicro with a TC620 temp sensor

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- Pj
  
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posted
16 years ago

Thu, Mar 6, 2008 7:13 PM

I'm trying to run some tests with the TC620. I want to pole the high out, low out and control using porta pins 0,1 and 2 of a pic 16f84f. All I get is garbage. Mircrochip says connect to the interups. My question is can the 620 interface directly with the pic, or do I need other components between the two chips? If so, why? I have the notes on the TC4469 quad CMOS driver, but I want to do some simple testing before complicating things. Any help will be appreciated.

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- Frank Buss
  
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posted
16 years ago

Fri, Mar 7, 2008 7:01 AM

The datasheet at

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says it has "logic output" (but doesn't define voltage levels), so it should be possible to connect the high limit, low limit and control to a PIC. Measure the voltages and compare it to the allowed input range for the PIC.

Maybe for testing this can be useful, but if you have already a PIC, you should use something like SE95 for temperature measuring, which is cheaper, too.

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Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

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- Fred Bloggs
  
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posted
16 years ago

Fri, Mar 7, 2008 10:19 AM

Looks like it has tons of drive. Maybe it's something else: "Care must be taken to ensure the LOW SET programming resistor is a smaller value than the HIGH SET programming resistor. Failure to do this will result in erroneous operation of the CONTROL output. Care must also be taken to ensure the LOW SET temperature setting is at least 5°C lower than the HIGH SET temperature setting. That is: LOW SET £ HIGH SET ? 5°C" Looks like about the only way to screw things up , assuming you know how to identify pin numbers correctly...