Sun Microsystems 220R service manual Functional Description, System Unit, 249

APPENDIX C

Functional Description

This appendix provides a functional description for the following:

Section C.1 “System Unit” on page 249

Section C.1.14 “Power Supply” on page 274

Section C.1.17 “Main Logic Board” on page 277

The following items are not supported on the Sun Enterprise 220R server:

Graphics and imaging card

4Diskette drive Audio card

C.1 System Unit

The system unit is an UltraSPARC port architecture (UPA)-based multiprocessor machine that uses peripheral component interconnect (PCI) as the I/O bus. The CPU modules, U2P ASIC (UPA-to-PCI bridge), and UPA graphics cards communicate with each other using the UPA protocol. The CPU modules and the U2P ASIC are UPA master-slave devices. The UPA graphics cards are UPA slave-only devices. The QSC ASIC routes UPA request packets through the UPA address bus and controls the flow of data using the XB9+ ASIC. For further information, see the following items:

Section C.1.1 “UPA” on page 252

Section C.1.2 “PCI Bus” on page 253

Section C.1.3 “UltraSPARC II Processor” on page 254

4Section C.1.4 “Memory System” on page 255 Section C.1.5 “Graphics and Imaging” on page 259

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