CCOMe-C79
CCOMe-C79 - Rev. First Edition: 1.0 - Last Edition: 1.0 - Author: A.R. - Reviewed by E.S. Copyright © 2021 SECO S.p.A.
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Smart Battery SM Bus Connector
The SM bus coming from COM Express module is carried directly both to the
Feature header (see par.3.3.8) and to a JST 4-pin connector CN29, p/n B4B-PH-K-
S(LF)(SN), or equivalent, which can be used for the connection of external Smart
battery controllers. Pinout as indicated in the left table.
SB_SMB_CLK: Smart Battery System Management bus bidirectional clock line,
+3.3V_ALW electrical level with
derived by SMB_CK signal
SB_SMB_DAT: Smart Battery System Management bus bidirectional data line, +3.3V_ALW
derived by SMB_DAT signal
SMB_ALERT#: System Management Bus Alert, active low input to the module that can be used to generate an Interrupt or to wake the system
RTC Battery
For the occurrences when the System (Carrier board + COM Express module) is not powered with an external power supply, on board there is a RTC Coin Cell
Battery holder CN9, for the use of standard coin battery type CR2032 with a nominal capacity of 220mAh, to supply, with a 3V voltage, the Real Time Clock and
CMOS memory mounted on the COM Express module.
The batteries should only be replaced with devices of the same type. Always check the orientation before inserting and make sure that they are aligned correctly and
are not damaged or leaking.
Never allow the batteries to become short-circuited during handling. Batteries supplied with C79 board are compliant to requirements of European Directive
2006/66/EC regarding batteries and accumulators. When putting out of order C79 board, remove the batteries from the board in order to collect and dispose them
according to the requirement of the same European Directive above mentioned. Even when replacing the batteries, the disposal has to be made according to these
requirements.
It is possible to monitor the consumption on VCC_RTC battery by removing the jumper from CN6
connector and inserting a tester in series set as ammeter between 2-3 position.
Alternatively, the consumption on VCC_RTC can be monitored by inserting a tester set as ammeter
between pin 1 and 2 of RTC Battery Sense Connector CN5.
CN5 is a dedicated 2 position Wire to Board Terminal Block, type Wurth p/n 691210910002
RTC battery can be enabled/disabled using dedicated jumper on CN6, which is a standard pin header, P2.54mm, 1x3 pin.
Smart Battery SM Bus Connector CN29
Pin Signal
Pin Signal
1
SB_SMB_CLK
3
SMB_ALERT#
2
SB_SMB_DAT
4
GND
CN6 position
RTC Battery enable
1-2
Battery disconnected
2-3
Battery connected
NO jumper
Current measurement
CAUTION: handling batteries incorrectly or replacing with not-approved devices may present a risk of fire or explosion.
