PT AMC131, Hardware Manual

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Chapter 6: Reset Configuration
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Hard Reset
Hard resets may originate from the following sources:
• MPC8641D-initiated system reset request
• Payload reset that can be initiated by:
– MMC
– Carrier board
• Front panel reset button
• Setting of custom bits
Payload Reset Initiated by the MMC
The MMC can drive a payload reset that results in a hard reset. The MMC circuitry has an
independent power-on reset circuit that is controlled by MMC power. A brown-out reset occurs
for the MMC when the MMC power drops below 2.7V. The MMC monitors the payload reset,
but does not allow this reset to directly reset the MMC circuitry.
A Watchdog timer within the MMC can reset the MMC.
The MMC ICE interface can directly reset the MMC.
Payload Reset Initiated by the Carrier Board
The carrier can reset the MMC directly through the ENABLE_N signal.
Front Panel Reset Button
When the system reset button (see Figure 2-1, “AMC131 Front Panel,” on page 23 ) on the front
panel is pressed, the AMC131 resets itself.
Soft Reset
Soft resets may be initiated through:
• The COP In-Circuit Emulator (ICE)
• The MPC8641D (limited to the processor)
Limited Resets
Limited resets include:
• Custom logic-initiated resets
• MMC resets
• Peripheral reset (DDR2 memory, Ethernet PHY, and USB Controller)
Caution:
Do not reset the DDR2. Attempting to reset this component results in module lockup. This
reset is used for initialization purposes only.