Sun Microsystems Ultra 5, Руководство по обслуживанию

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C-24 Sun Ultra 5 Service Manual • February 2000
The flash PROM is divided into two halves, the open boot PROM (OBP) half, and
the power-on self-test (POST)/open boot diagnostic (OBDiag) half. There are two
physical jumpers on the motherboard. One jumper is used to enable either ROMBO
or the on-board flash. The second jumper protects the flash prom from accidental
writes to the flash PROM.
C.1.6.4 NVRAM/TOD
The non-volatile RAM/time of day (NVRAM/TOD), is an 8K x 8 nonvolatile static
RAM and real-time clock. The programmable alarm output is used for turning the
system on when Energy Star is enabled and the system has turned itself off. The
following figure shows the NVRAM/TOD functional block diagram.
FIGURE C-13
NVRAM/TOD Functional Block Diagram
C.1.6.5 Audio
The system audio consists of a single-chip CODEC, integrated amplifier, and
supporting analog circuitry.
The CODEC is a single-chip stereo, analog-to-digital and digital-to-analog converter
based on delta-sigma conversion technique. The microphone input specifications are
designed for the SunMicrophone II or equivalent. The following figure shows a
functional block diagram of the system audio circuit.
TABLE C-7
lists the audio input
electrical specifications and
TABLE C-8
lists the audio output electrical specifications.
A[12:0]
ED[7:0]
POWERON_L
E
TOD_CS_L
IRQ
W
TOD_WE_L
To
power supply
NVRAM/TOD