PT AMC123, Руководство пользователя

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Chapter 6
Reset
Overview
This chapter discusses the various reset types and reset sources on the AMC123. Because
many embedded systems have different requirements for board reset functions, the
incorporation of this sub-system on the AMC123 has been designed to provide maximum
flexibility.
Key topics in this chapter include:
• “Reset Types and Sources,” on page 89
• “Power Reset,” on page 89
• “Hard Reset,” on page 90
• “Soft Reset,” on page 91
• “Limited Resets,” on page 91
• “NMI/SMI/SERIRQ Sources,” on page 91
Reset Types and Sources
The AMC123 supports the following reset types that affect the entire module. All resets are
specific to the MMC or payload circuitry and one does not affect the other.
• Power reset
• Hard reset
• Soft reset
Limited resets that do not affect the entire board are also supported.
Power Reset
Power reset occurs when the power-on reset device changes from a power-off to a power-on
state. The power-off to power-on state occurs when either the payload power is turned on or
when the power good indication from the DC-to-DC converters is false and returns true.
A power reset also generates a hard reset.
FCLKA
The AMC123 is held in reset until the PCI Express reference clock (FCLKA) source is
determined. The AMC.1 R2.0 specification requires that FCLKA is e-keyed. The AMC123 is
shipped from the factory configured for AMC.1 R2.0 e-keying of FCLKA. AMC.1 R1.0 carriers
do not e-key FCLKA. If the AMC123 does not come out of reset when powered on, it is likely
that FCLKA is not configured properly for the specific carrier. See
“CMOS Reset, FCLKA, SSC,
and COM1 Redirection Switch (SW2),” on page 42 for information on configuring FCLKA.