Saturn User Manual V1
Page 11
3.2.11 RTC Backup Battery
The RTC current consumption is 6uA with RTC voltage at 3.0V while the system is in a mechanical off (G3) state
at room temperature. This data can be used to estimate the battery life. The voltage of the battery can affect the
RTC accuracy. In general, when the battery voltage decays, the RTC accuracy also decreases
An onboard 2032 coin cell battery holder and battery are provided on the bottom side of the board, accessible
through a cutout in the heat spreader. A 1x2 connector is also provided to enable the use of an external battery for
rugged applications.
Batteries are rated by storage capacity in milli-ampere hours (mAh). The battery life can be calculated by dividing
the battery
’s capacity by the average RTC current required and considering external factors that effects the battery
life. For example, if the battery storage capacity is 190 mAh (assumed usable) and the average current required is
6 μA, the ideal battery life will be: 190,000 μAh/6 μA = 31,667 h = 3.6 years.
External Battery voltage specification: Typical 3.0V; Max: 3.2V; Min: 2.0V
The board can boot and function properly without a backup battery installed.
3.2.12 Trusted Platform Module (TPM)
The board contains Infineon’s SLB 9670XQ2.0 TPM module featuring a fully TCG TPM 1.2/2.0 standard compliant
module with an SPI interface. TPM can be used as a root of trust for platform integrity, remote attestation, and
cryptographic services.
3.2.13 PCIe link routing
Apollo lake processor supports 4 PCIe 2.0 ports and 6 lanes can be allocated over those 4 ports. Bypass option is
provided for I210 Gbe Controller 2 by removing PCIe switch for the configuration where PCIe switch and PCIe/104
connector is not used.
The PCIe port mapping is as below:
PCIe Port No.
Lane Width
Port Termination
Port 1
X2
1:4 PCIe Switch
•
Three x1 lanes to one bank PCIe/104 connector
•
One x1 lane to I210 Gbe controller 2
Port 2
x1
I210 Gbe controller 1
Port 3
x1
One bank PCIe/104 connector Port1
Port 4
x1
Minicard socket
3.2.14 PCIe/104 OneBank Expansion
The board offers expansion over one bank PCIe/104 connector with taller 22mm stacking height to ensure clearance
over an installed minicard module on the main board.
The OneBank specification supports up to four x1 lane PCIe ports on one bank PCIe/104 connector, and all four
lanes are supported on Saturn. The PCIe lane mapping on the one bank PCIe/104 connector is as below:
PCIe Lane No.
PCIe Host
Lane 0
Directly from the processor
Lane 1
Indirectly from the processor via 1:4 PCIe switch
Lane 2
Lane 3
5V from input power connector is directly connected PCIe/104 connector so that the board can either powered by
input power connector or PCIe/104 one bank connector. Option to disconnect 3.3V to the PCIe/104 connector is
provided.
