HP 330 Service Information Manual page 70

RAM is 32 bits wide. The cache fills at 22 Mbytes per second. The architecture comprises
separate system bus (memory) and I/O busses. RAM is a dual-port design so the CPU and
the I/O subsystem access RAM very nearly simultaneously, without contending for bus control.
System performance is enhanced by the MC68020 executing program code with minimal conflict
from I/O traffic to and from the disc drive.
Board size for the processor, RAM and system interface board is the "System Board" size of
the Model 320. RAM boards provide up to 16 Mbytes per system slot. Two slots are available
for a total supported physical RAM capacity of 32 Mbytes on the Model 350.
Computer Packaging
Each is packaged in a Series 300 chassis like
t~e
Models 310 and 320. For most applications, an
expander is not necessary due to higher integration of components.
The computer has four system slots for the processor, RAM board, system interface board, and
video board. Each system slot is part of the new DIO-II 32-bit backplane. DIO-II is made
up of a two-connector system. The first is identical to the Series 200/300 DIO connector. A
second, or DIO-II connector adds eight address lines, sixteen data lines and more control lines.
When used with the signals on the DIO connector, they allow 32-bit address and data transfers.
DIO-II is designed to be compatible with DIO in two ways:
• DIO bus masters, like the DOS Co-processor, can talk to DIO-II boards.
• DIO-II bus masters like the processor and DMA on the systenl interface board, can talk
to DIO accessory and video cards.
System" Implementation
Figure 3-3 is a diagram of a typical configuration.
Processor Board
• Model 330 - 16 MHz MC68020, 16 MHz MC68881 coprocessor, MC68851 PMMU, 4
Mbytes RAM.
• Model 350 - 25 MHz MC68020, 20 MHz MC68881 coprocessor, custom 25 MHz MMU,
32- KByte cache.
RAM Boards
The following RAM boards are supported ONLY in the computer:
• HP 98258A 4 Mbyte RAM Controller Board (Model 330 or 350).
• HP 98258B 4 Mbyte RAM Add-On Board (installed on the 4 Mbyte RAM controller
board in a Model 350 only).
• HP 98258C 12 Mbyte RAM Add-On Board (installed on the 4 Mbyte RAM controller
board in a Model 350 only).
• Model 350 - Includes one 2-board 8 Mbyte assembly: one 4 Mbyte RAM Controller Board
with a 4 Mbyte Add-On.
54
Functional Description