Artesyn COMX-P1022 Installation and Use (July 2014) - Manual (Page 62)

Functional Description
COMX-P1022 COM Express Module Installation and Use (6806800M04C) 62
The ADT7461 can accurately measure the temperature of a remote thermal diode to ±1°C and
the ambient temperature to ±3°C. The temperature measurement range defaults to 0°C to
+127°C, but can be switched to a wider measurement range of?55°C to +150°C. The ADT7461
communicates over a 2-wire serial interface compatible with system management bus
(SMBus) standards. An ALERT output signals when the on-chip or remote temperature is out of
range. The THERM output is a comparator output that allows on/off control of a cooling fan.
The ALERT output can be reconfigured as a second THERM output, if required.
By default, u-boot should mask THERM and ALERT output, set the temperature measurement
range to 0°C to +127°C. And u-boot should provide u-boot commands for setting operation
mode, and getting the monitoring temperature.
4.6.4 SODIMM SDP EEPROM
The SODIMM SDP EEPROM is connected to I2C#2. I2C address for SDP EEPROM of memory
module is 0xA6 and 0x66.
Commonly the memory module information on SDP EEPROM can be used to configure the
memory controller. But in this case, we use fix parameters to configure the memory controller,
so the BSP won't read the SDP EEPROM.
4.6.5 RTC and Watchdog Timer
The RTC/WDT M41ST85W is located on I2C#2, and the device address is 0xD0.
The M41ST85W is a combination Serial Real-Time Clock, Microprocessor Supervisor, and
NVRAM Supervisor. It is built in a low power CMOS SRAM process and has a 64-byte memory
space with 44 bytes of NVRAM and 20 memory-mapped RTC registers. The RTC registers are
configured in binary coded decimal (BCD) format. The M41ST85W has 512-bit, static CMOS
SRAM organized as 64 words by 8 bits. A built-in 32.768 kHz oscillator and 8 bytes of the SRAM
are used for the clock/calendar function and are configured in binary coded decimal (BCD)
format. An additional 12 bytes of RAM provide status/control of Alarm, Watchdog and Square
Wave functions. Addresses and data are transferred serially via a two line, bi-directional I2C
interface. The built-in address register is incremented automatically after each WRITE or READ
data byte. The M41ST85W can detect power failures and automatically switches to the battery
supply when a power failure occurs. The energy needed to sustain the SRAM and clock
operations can be supplied by a small lithium button-cell supply when a power failure occurs.