Technical data

CHALLENGE/Onyx Diagnostic Road Map 1-7
Figure 1-4 Everest Buses and Interface ASICs
1.2.2 Polled Serial Bus
This dedicated bus is embedded in the system’s backplane. It connects the system’s CPU
boards with the System Controller. During the boot process, the System Controller polls the
CPU boards over this bus, requesting a bootmaster CPU. After the bootmaster is identified,
all bring-up messages from the bootmaster CPU are sent to the System Controller display
over the polled serial bus. The bootmaster CPU also outputs the bring-up messages to the
system console RS-232 port (see Figure 1-5).
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IP19/IP21
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IP19/IP21
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IP19/IP21
MD
IO4 IO4
Address Bus (50 bits)
Data Bus (256)
MD MD MD MD MD MD MD MD MD