Kontron AM4521 - Manual (Page 16)

5 AM4521
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2.2.1 SAS Port Isolation Multiplexer Circuit
The AM4521 includes SAS re-transmitter circuits that can be used to adjust or "wave-shape" the transmit
signal characteristics driven out the AMC finger connections (storage signaling ports 2 and 3). At
manufacturing time, this circuit is pre-set to values that are optimal for the majority of deployments.
Programmable parameters include:
• Transmit pre-emphasis (five levels)
• Receiver equalization (three levels)
• Transmit output swing to support SAS up to 1600mV
Tools are available to adjust these circuits to accommodate a typical backplane or cable situations. Please
contact your Kontron technical support department if you feel your deployment will require different
settings.
2.3 IPMI Subsystem
The IPMI subsystem provides module management control (MMC) for the board. It is based on an Atmel
microcontroller. Its function is to monitor module functions such as power, temperature, and hot swap
requests via the ejector handle and report these to the base controller in the enclosure. It also stores
information about the module including serial number and E-Keying.
2.4 IPMI and Management Controller (IPMC)
The design features an IPMI controller consisting of a 16-bit microcontroller, flash and SRAM. The
microcontroller uses I2C interface to communicate the shelf management controller (ShMC), and sensors and
MMC devices on AdvancedMC modules.
• An I2C connection provides the communication path between the MMC the temperature sensor. The I2C
serial bus also routes to the SFP+ modules.
• Support hot-swap operation as defined for AMC modules in PICMG AMC.0 specification "Fail-safe flash
update" - if interrupted at anytime, the MMC firmware is still able to respond and re-flash.
• "I2C hang recovery" - able to detect and recover from an I2C bus hang.