can I switch btw i2c and i/o config as 2 wire communication?

qtthuan · Joined: 06 Jul 2011 Posts: 4 Location: Canada

Hi all,

I'm new to this program stuff and current using pickit3 with the pic12lf1822. I have a temperature sensor (i2c) and humidity sensor (2wire communication that is not compatible with i2c). I got the I2C working ok but when I try to use the scl and sda as general i/o to produce 2 wire communication it does not work. Can I switch between the i2c and general i/o for the 2 wire communication? If so how do i do that? Thank you.

Best Regards,

Tony.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

I guess this means you are using the hardware i2c module (MSSP) and
you want to disable it, and use those pins for general purpose i/o.
This line should do it:

qtthuan · Joined: 06 Jul 2011 Posts: 4 Location: Canada

Yes that's it. One more question. Do you have any example code to generate clk and data using the general purpose i/o for the 2 wire communication? Its similar to i2c format but the start condition is different. I took care of the start condition. I don't know how to generate the 9 clk with 8 bit data and ack bit at 100khz for read and write.

Thank you.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Post the manufacturer and part number of the humidity sensor. There
may already be a driver posted on the forum.

qtthuan · Joined: 06 Jul 2011 Posts: 4 Location: Canada

manufacturer: Sensirion
MFG PN: SHT71

dyeatman · Joined: 06 Sep 2003 Posts: 1934 Location: Norman, OK

There is a driver for the SHT75 in the Code Library which should be the same...
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qtthuan · Joined: 06 Jul 2011 Posts: 4 Location: Canada

Found it. thank you.