STCOM Datasheet, PDF (28/58 Pages) STMicroelectronics – Powerline communication and application system-on-chip

Description
STCOM
1.11
Temperature sensors and overtemperature protection
The STCOM embeds an overtemperature protection mechanism, with fixed temperature
threshold, preventing the device from overheating. This automatic protection acts by
shutting down the PLC line driver when overheating occurs during PLC transmission. The
normal operation of the line driver is restored automatically as the overtemperature event
has ended.
In addition to the overtemperature automatic protection, information from two temperature
sensors is provided:
 The line driver temperature sensor
 The low power temperature sensor
The first sensor monitors the line driver temperature and can be used by the RTE to prevent
the line driver to be shut down abruptly by the overtemperature protection. The way to use
this information may depend on the protocol and on the version of the RTE firmware, so its
usage (if any) will be described within the specific firmware documentation released by
STMicroelectronics^®.
The second sensor monitors the temperature of the low power section of the device. It is
internally connected to the channel 8 of the general purpose 12-bit ADC (see Section :
General purpose analog-to-digital converter (ADC) on page 19 for further details) and it can
be used by the application for its own purposes.
The accuracy of the sensors is guaranteed by design. In case a higher accuracy is required
on the low power temperature sensor, the user shall adopt its own calibration procedure
during the application manufacturing.
1.12
Boot modes
The STCOM provides different security levels of protection:
1. Level 1: unsecure
The Cortex™-M4 is accessible through the JTAG and it's possible to download the
firmware in the embedded Flash using debugger plug-in or to load it from the external
NVM using the system boot functionality. It's also possible to download customer OTP
data such as cryptography keys. The shadow sector is not accessible.
2. Level 2: secure
The JTAG is blocked and it's not possible to access the embedded Flash for external
read or write operation. It's possible to load the ciphered firmware image from the
external NVM and upgrade the firmware thanks to the IAP functionality. Read access to
the embedded Flash is possible to the Cortex^TM-M4 code, including the shadow sector.
3. Level 3: secure and locked
The JTAG is blocked and it's not possible to access the embedded Flash for external
read or write operation. Some embedded Flash sectors are locked. It's possible to
upgrade the firmware thanks to the IAP functionality unless the new image tries to
change a locked area. Read access to the embedded Flash is possible to the
Cortex^TM-M4 code, including the shadow sector.
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