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68 SBC329 3U VPX Single Board Computer
Publication No. SBC329-HRM/1
5.17.2
SDRAM SPD EEPROM
The SBC329 provides a combined 4 Kbit EEPROM and temperature sensor device,
which is compatible with the JEDEC TSE2004av standards.
A JEDEC-compatible Serial Presence Detect (SPD) image, which contains timing and
configuration data for the DDR4 SDRAM is loaded into this device. This emulates
the case of a DIMM being fitted, and allows the BIOS to use standard routines to
detect and configure the memory during boot-up.
Write protection on this device is set by configuring an on-chip register. By default,
this device is write protected, and it can be write-enabled by invoking a routine in
the BIOS setup screens. This can only be done when a jumper is fitted on the
Configuration EEPROM Write Enable Link (P6)
) is inactive.
NOTES
The write-protection status can only be changed when a TAC is fitted to the SBC329.
The integrated temperature sensor in this device is not used by software and is not available for
customer use. However, it will respond to relevant addresses on the SMBus.
5.17.3
Elapsed Time Indicator
A Dallas DS1682 ETI logs the amount of time for which the SBC329 has been
powered, and the number of power cycles. Power-up time is only recorded when the
platform is fully powered and not in S3, S4 or S5 states. Power cycle events are only
recorded when any of the backplane supplies transition from on to off.
The ETI is intended only to be used by Abaco software drivers. See the relevant
software manual for details.
LINK
For more details on the ETI device, see
5.17.4
Accelerometer
An ST Microelectronics LIS331HH three-axis MEMS accelerometer is fitted to the
SBC329. This device provides the ability to detect excessive vibration levels and
board orientation.