ADLINK Technology arm AMPERE COM-HPC-ALT User Manual page 20

COM-HPC-ALT User's Guide PICMG COM-HPC R1.0
It is anticipated that in most situations the BMC, if deployed, will be on the Carrier. Implementation of OOB management and a BMC on the Carrier is
entirely optional. A Carrier based BMC is intended to work in conjunction with a Module based microcontroller referred to as the MMC (described
below).
A Carrier BMC, if deployed, shall implement an IPMB interface to the COM-HPC Module. This is the channel for IPMI support. The Carrier BMC may also
make use of the COM-HPC I2C0, USB, eSPI, NBASET0, UARTx and / or the PCIe_BMC interfaces, as well as controlling the module power signals like
PWRBTN, ...).
Any COM-HPC USB host port may be used to interface to a Carrier BMC USB client port. The Module USB port is usually a Module chipset or SOC host
port, and not a MMC USB port. Designers should avoid using COM-HPC USB0, as it has special privileges allowing it to be used as a host or client.
Designers may want to avoid using COM-HPC USB0, 1, 2, 3 as they are defined to allow USB SuperSpeed capability and BMC devices to not typically
have USB SuperSpeed capability. USB4, 5, 6 or 7 should be used for the BMC interface if available.
Of the two COM-HPC UART interfaces that may be used to interface to a Carrier BMC, UART1 should be selected as UART0 is often used for functions
such as Console Redirect.
MMC (Module Management Controller) (Located on COM-HPC Module, optional)
The MMC is a Module based microcontroller that may work in conjunction with a Carrier based BMC. If there is no Carrier BMC, then the MMC shall fall
back to a mode that does not depend on the Carrier BMC, allowing the Module to function without external OOB management. The MMC shall
powered by the VCC_5V_SBY supply to allow for OOB functionality even when the main supply is not available, however, it should also use the main
VCC rail, if available.
In most implementations, the MMC will be a relatively small low cost and low power device, in order to keep Module costs down for customers that do
not require OOB management features. It may serve as a sensor aggregator. It may serve as host for nonvolatile Module parameter storage.
The MMC, if implemented, shall include an IPMB slave interface. It may additionally interface to the Carrier BMC over any of several other COM-HPC
interfaces, including the I2C0 and or UART0 ports.
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