User Manual
BCM1250/BCM1125/BCM1125H
10/21/02
B r o a d c o m C o r p o r a t i o n
Document
1250_1125-UM100CB-R
Section 1: Introduction
Page
3
T
HE
BCM1125
AND
BCM1125H
The core of the BCM1125 and BCM1125H is a uniprocessor system consisting of a Broadcom SB-1 high
performance MIPS64 CPU, a 256K L2 cache and a DDR SDRAM memory controller. Two integrated 10/100/
1000 Ethernet MACs enable easy interfacing to LANs. The two network interfaces can also be operated
together to give a 16 bit wide interface that can run full-duplex at OC-48 rates. Two serial ports are provided
for use as UARTs or for WAN connections at up to T3/OC-1 rates (55Mbit/s). High speed I/O is provided on
the BCM1125H using the HyperTransport (formerly called “Lightning Data Transport” or “LDT”) I/O fabric. Both
the BCM1125 and BCM1125H have a 66 MHz PCI (rev 2.2) local bus. To enable low chip count systems both
parts include a configurable generic bus that allows glueless connection of a boot ROM or flash memory and
simple I/O peripherals. On-chip debug, trace and performance monitoring functions assist both hardware and
software designers in debugging and tuning the system. The system can be run either big endian or little
endian.
Figure 2: BCM1125/H Block Diagram
A
UDIENCE
This User Manual includes information that is needed when writing software for the BCM1250, BCM1125 or
BCM1125H. It provides a system overview for Systems and Hardware Designers. This User Manual is
common across the parts, reflecting their software compatibility. Each part has an individual Data Sheet
containing detailed hardware information. (Note that some hardware details of the BCM1250 that were in
previous versions of the User Manual are now found only in the Data Sheet.)