RS8234EBGC Mindspeed Technologies, RS8234EBGC Datasheet - Page 244

• Manufacturer Part Number: RS8234EBGC
• Description: RS8234EBGC ATM XBR SAR
• Manufacturer: Mindspeed Technologies

10.0 Local Processor Interface
10.1 Overview
10-2
i960CA 32-bit architecture and is completely compatible with the i960CA/CF
and the new i960Jx processors. Other synchronous and asynchronous processors
(e.g., from Motorola, AMD, IDT) can be interfaced using external circuitry. The
only requirement is that the processor have a 32-bit bus and that the control
signals be synchronized to SYSCLK.
must arbitrate with the RS8234 for access to the memory controller. Due to the
requirements of reassembly and segmentation access to SRAM, and the
implications of PCI bus utilization, the local processor has the lowest priority in
the memory arbitration scheme. Since the local processor is typically used for low
bandwidth supervision and maintenance functions, this should be acceptable.
SRAM or SAR shared memory, a local processor memory request is generated
internal to the RS8234. The memory arbiter then coordinates this request with
requests from other memory consumers, and grants the memory bus to the local
processor at the appropriate time. The local processor is held off during this
process by the insertion of a variable number of wait states, accomplished by the
i960 withholding READY* or RDYRCV*. Once the local processor is granted
the memory system, the transceivers are enabled to allow the local processor’s
address and data to access the SRAM or control registers. The conclusion of the
data transaction is signaled by the assertion of PRDY*. Wait states may be
inserted by the processor at any time by asserting PWAIT*. The last data cycle in
a burst is indicated by the PBLAST* signal. In this manner, non-i960 processor
half-speed buses or slow transceivers can be accounted for.
wait state between the first access in a burst and subsequent accesses. This can be
used to simplify the design of memory controllers for processors that do not
produce a wait output and which require more time between data cycles in a burst.
The processor interface is a generic synchronous interface based on the Intel
To access the RS8234 SAR shared memory or control registers, the processor
When the local processor accesses the RS8234’s control registers, internal
The LP_BWAIT bit in the CONFIG0 Register will automatically add a single
Mindspeed Technologies
ATM ServiceSAR Plus with xBR Traffic Management
™
28234-DSH-001-B
RS8234