CN8478 Datasheet, PDF (61/221 Pages) Conexant Systems, Inc – Multichannel Synchronous Communications Controller (MUSYCC)

3
3.0 Expansion Bus (EBUS)
MUSYCC provides a PCI bridge to a local bus interface on MUSYCC called the
Expansion Bus (EBUS). The EBUS provides a host processor across the PCI bus
to access up to 1 MB of peripheral memory space on the EBUS.
Although EBUS utilization is optional, the most notable application for the
EBUS is the connection to peripheral devices (e.g., Bt8370 T1/E1 framers) local
to MUSYCC’s serial port. Figures 3-1 and 3-2 illustrate block diagrams of the
EBUS interface with and without local Multiprocessor Unit (MPU).
Figure 3-1. EBUS Functional Block Diagram with Local MPU
Clock
Address/Data
Interrupt
EBUS
Interface
Regenerated
and
Inverted
Bus
Arbiter
Local
Expansion
Bus
Clock
Address/Data
Control
Bus Arbitration
EINT*
MPU
Intel
Motorola
T1/E1
Framer
Bt8370
8478_007
Figure 3-2. EBUS Functional Block Diagram without Local MPU
EBUS
Interface
Clock
Address/Data
Control
EINT*
Local RAM
Downloadable
ROM
Peripheral
Devices
8478_008
100660E
Conexant
3-1