Artesyn ATCA-9405 Installation and Use (May 2014) - Manual (Page 75)

Service Processor
ATCA-9405 Installation and Use (6806800M71G) 75
4.4.5 Thermal Sensor
Majority of DDR3 Registered DIMMs contain a Thermal Sensor on DIMM (TSOD) and its output
is tied to EVENT# pin187 on the DIMM. This signal is an active low signal and is used by the
DIMM to notify the Processor or system management device that its thermal sensor has
crossed a thermal threshold. The thermal sensor is readable by P2020 and by the IPMC. The
EVENT# interrupt is connected to the FPGA (which is responsible for interrupt routing).
4.5 SP U-Boot
After power up or reset, the following necessary steps are taken by P2020 processor:
 boot from active SPI Boot Flash
 initialize PCIe infrastructure
 initialize network infrastructure
 power-up Packet Processors
 initialize PCIe interfaces of Packet Processors
 boot Packet Processors via PCIe
4.5.1 Environment Variables
U-Boot uses environment variables to both control the behaviour of various U-Boot
components and to report information to user applications.
The working set of the U-Boot environment variables is stored in memory and can be accessed
using the setenv and getenv commands. The values of environment variables can be:
 The content of the NVRAM (an I2C EEPROM), or (if the NVRAMs CRC is invalid) a set of
compiled-in defaults.
 The content of the IPMI boot parameter storage
 Dynamic variables set during the boot-up phase
 Variables set by the user via the U-Boot shell.