Boot Strap Signals - Seco COMe-C55-CT6 User Manual

Com express type 6 module with the intel 8 th generation core and celeron 4000 cpus

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3.2.5.18 GPIO interface signals

According to COM Express

specifications rel. 3.0, there are 8 pins that could be used as General Purpose Inputs and Outputs OR as a SDIO interface.

The SDIO signals managed by the embedded PCH, however, on COMe-C55-CT6 module are used to drive the onboard microSD card slot (see par. 3.2.3)

For this reason, the COMe-B75-CT6 module use these pins only for the connection of four General Purpose Inputs and four General Purpose Outputs, which are

managed though the embedded microcontroller.

Signals involved are the following:

GPI[0÷3]: General Purpose Inputs, electrical level +3.3V_ALW with 10kΩ pull-up resistor each.

GPO[0÷3]: General Purpose Outputs, electrical level +3.3V_ALW with 10kΩ pull-down resistor each.

3.2.6

BOOT Strap Signals

Configuration straps are signals that, during system reset, are set as inputs (independently by their behaviour during normal operations) in order to allow the proper

configuration of the processor / PCH. For this reason, on COMe-C55-CT6 are placed the pull-up or pull-down resistors that are necessary to configure the board

properly.

The customer must avoid to place, on the carrier board, pull-up or pull-down resistors on signals that are used as strap signal, since it could result in malfunctions of

COMe-C55-CT6 module.

The following signals are used as configuration straps by COMe-C55-CT6 module at system reset.

SPKR: pin B32 of connector AB. +3.3V_ALW voltage signal with PCH internal weak pull-down. Used to disable the PCH

SMB_ALERT#: pin B15 of connector AB. +3.3V_ALW voltage signal with 1kΩ pull-up resistor. Used to enable CSME Crypto Transport Layer Security (TLS) cipher

suite and support Intel

AMT with TLS (Transport Layer Security).

SPI_MOSI: pin A95 of connector AB. Electrical level +3.3V_ALW with 3k2Ω pull-up resistor. This signal must always sample high during strap sampling.

HDA_SDOUT: pin A33 of connector AB. Used to disable Flash Descriptor Security. Signal at +3.3V_ALW voltage level with an internal weak pull-down resistor.

COMe-C55-CT6

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