4 temperature sensor, 5 smarc sat30 power management, Temperature sensor – Kontron SMARC-sAT30 User Manual
Page 74: Smarc sat30 power management
User’s Guide
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5.4
Temperature Sensor
The SMARC sAT30 module features a temperature sensor available on the I2C_PM bus. An On Semiconductor NCT72
has been used to implement this feature. I2C address information to access this device is provided in
section 3.2.22
The temperature sensor allows two temperatures to be read: 1) the Tegra SoC internal thermal diode and 2) the sAT30
Module ambient PCB temperature.
The temperatures can be read via Linux command line functions, or via the BSP.
To read the CPU temp, run the commands:
i2cget –y 0x4c 0x01
i2cget –y 0x4c 0x10
The first command gives you the temp (in binary) in 1°C increments.
The second command gives you added granularity (in binary) in 0.25°C increments. (Only the two MSB’s are
used, so you will only get; 0x00, 0x40, 0x80, 0xc0 for 0.0, 0.25, 0.50 and 0.75, respectively.
To read the local (NCT72 measured/ambient) temp run:
I2cget –y 0x4c 0x00
This will return the local temp (in binary) in 1°C increments.
There is no added granularity register for the local temp.
The CPU thermal diode readout is a valuable tool to use during system development. It should be used to characterize
and qualify the system thermal solution.
5.5
SMARC sAT30 Power Management
The SMARC sAT30 module supports the following system and power management modes:
»
LP0 (Deep Sleep Mode).
»
LP1 (Sleep Mode).
»
Active Mode.
Low Power mode support and supported resume events are software dependant. Please consult the software release
notes available with the SMARC sAT30 board support package a