Technical data

Central Processor Unit, Continued
Sound generator
Four asynchronous lines
Time-of-Year clock
Ethernet identification ROM
NVAX CP-Bus
Bus Adapter
To provide buffering and connection to the I/O devices, the KA49
contains a DC243, NDAL to CDAL adapter (NCA). The NCA
provides an interface between the NVAX NDAL bus and two CP-
Buses where the I/O device adapters reside. As a bus adapter, the
NCA controls transactions between the higher performance NDAL
bus and the lower performance CP-Buses. Each of the NCA’s
CP-Bus ports provide a CVAX compatible peripheral bus for direct
memory access (DMA) by peripheral devices.
Small
Computer
Systems
Interface
NCR 53C94 implements the small computer system interface
(SCSI) bus interface. It has a single port, connecting both to
devices within the BA46 system box and allowing for expansion
externally.
Ethernet
Interface
The Ethernet interface handles communications between the CPU
module and other nodes on the Ethernet. It is implemented with
the second generation Ethernet controller chip (SGEC) onboard
network interface. Used in connection with the module backpanel,
the SGEC allows the KA49 to connect to either a ThinWire or
standard Ethernet. It supports the Ethernet data link layer and
provides CP-Bus parity protection.
Optional
Bus Adapter
Interface
The optional bus adapter provides a translation between one of
the CP-Buses and the adapter bus. The VAXstation 4000 Model
90 has direct, transparent access to the bus adapter. The slot
appears as a region of memory in the workstation’s I/O space.
The bus adapter option can perform DMA to any location in the
memory space of the VAXstation 4000 Model 90. This DMA can be
done either directly to the physical memory of the workstation or
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