Kontron AM4500 User Manual page 20

2.4.6.1 Hot-Swap Process
The AM450x AMC has the ability to be hot-swapped in and out of a AMC Carrier. The onboard MMC manages
the AMC's power-up and power-down transitions. The list below illustrates this process for power down
request.
1 Ejector latch is opened. HOT_SWAP_PB# assertion. MMC firmware detects the assertion of this signal.
2 MMC sends "Module Handle Open" event message to AMC Carrier. The corresponding M state of AMC
Carrier moves from M4-> M5.
3 AMC Carrier moves from M5 -> M6 if the SHMC grants the request and then send the FRU Control
requesting quiesced state to the AMC.
4 The firmware deasserts payload power and sends "Module Quiesced" event message to the AMC Carrier
where it transitions from M6 to M1 state.
2.4.6.2 Hot-Swap LED
The AM450x supports a blue Hot Swap LED mounted on the front panel. This LED indicates when it is safe to
remove the AMC from the AMC Carrier. The on-board MMC drives this LED to indicate the hot-swap state. The
following states are possible:
LED state Description
OFF AMC is in M4 state, normal state when board is in operation.
ON Ready for hot swap.
Short blink M5 state deactivation request. Indicates deactivation is in progress.
Long blink M2 state Activation Request. Indicates activation is in progress.
When the AMC latch is disengaged from the faceplate, the hot swap switch embedded in the PCB will assert a
"HOT_SWAP_PB#" signal to the MMC, and the MMC will send Module Handle Open" event message to the
AMC Carrier which move from the M4 state to the M5 state. At the M5 state, the AMC Carrier will ask the SHMC
(or Shelf Manager) for permission to move the AMC to the M6 state. Then the Carrier AMC will set the AMC Hot
Swap LED to indicate this state with a short blink. Once permission is received from the SHMC or higher-level
software, the AMC will move to the M6 state.
The SHMC or higher level software can reject the request to move to the M6 state. If this occurs, the AMC will
return the Hot Swap LED to a solid off condition, indicating that the AMC has returned to M4 state.
If the AMC reaches the M6 state through an extraction request through the AMC handle latch, the MMC
communicates to the AMC Carrier that the module must discontinue operation in preparation for removal.
The Hot Swap LED continues to flash during this preparation time, just like it does at the M5 state. When
main AMC payload power is successfully removed from the AMC Bay, the Hot Swap LED remains lit, indicating
it is safe to remove the AMC from the AMC Carrier.
9
Board Features
AM450x User's Guide