I’m trying to read temperature from a sensor connected to an I2C port on the J21 expansion header.
The sensor is an LM75B http://www.nxp.com/documents/data_sheet/LM75B.pdf
I installed i2c-tools to peek at the data.
The sensor’s i2c address is 0x42, and since it’s connected to pins I2C_GP_DAT (pins 3 and 5), I would expect i2c_detect -y 0 to show this address as available, and then be able to use i2cdump to read sensor data.
However, the sensor does not show up.
Any suggestions on how to properly read/write data to an I2C device connected to the header?