Книга: Embedded Linux Primer: A Practical, Real-World Approach
3.2.5. Broadcom MIPS
3.2.5. Broadcom MIPS
Broadcom is a leading supplier of SOC solutions for markets such as cable TV set-top boxes, cable modems, HDTV, wireless networks, Gigabit Ethernet, and Voice over IP (VoIP). Broadcom's SOCs have been very popular in these markets. We mentioned earlier that you likely have Linux in your home even if you don't know it. Chances are, if you do, it is running on a Broadcom MIPS-based SOC.
In 2000, Broadcom acquired SiByte Inc., which resulted in the communications processor product lineup the company is currently marketing. These processors currently ship in single-core, dual-core, and quad-core configurations. The company still refers to them as SiByte processors.
The single-core SiByte processors include the BCM1122 and BCM1125H. They are both based on the MIPS64 core and operate at clock speeds at 400-900MHz. They include on-chip peripheral controllers such as DDR SDRAM controller, 10/100Mbps Ethernet, and PCI host controller. Both include SMBus serial configuration interface, PCMCIA, and two UARTs for serial port connections. The BCM1125H includes a triple-speed 10/100/1000Mbps Ethernet controller. One of the more striking features of these processors is their power dissipation. Both feature a 4W operating budget at 400MHz operation.
The dual-core SiByte processors include the BCM1250, BCM1255, and BCM1280. Also based on the MIPS64 core, these processors operate at clock rates from 600MHz (BCM1250) to as high as 1.2GHz (BCM1255 and BCM1280). These dual-core chips include integrated peripheral controllers such as DDR SDRAM controllers, various combinations of Gigabit Ethernet controllers, 64-bit PCI-X interfaces, and SMBus, PCMCIA, and multiple UART interfaces. Like their single-core cousins, these dual-core implementations also feature low power dissipation. For example, the BCM1255 features a 13W power budget at 1GHz operation.
The quad-core SiByte processors include the BCM1455 and BCM1480 communications processors. As with the other SiByte processors, these are based on the MIPS64 core. The cores can be run from 800MHz to 1.2GHz. These SOCs include integrated DDR SDRAM controllers, four separate Gigabit Ethernet MAC controllers, and 64-bit PCI-X host controllers, and also contain SMBus, PCMCIA, and four serial UARTs.
Table 3-7 summarizes select Broadcom SiByte processors.
Table 3-7. Broadcom Select SiByte Processor Highlights
| Feature | BCM1125H | BCM1250 | BCM1280 | BCM1480 |
|---|---|---|---|---|
| Core/speeds | SB-1 | Dual SB-1 | Dual SB-1 | Quad SB-1 |
| MIPS64 | MIPS64 | MIPS64 | MIPS64 | |
| 400-900MHz | 600-1000MHz | 800-1200MHz | 800-1200MHz | |
| DRAM controller | Y-DDR | Y-DDR | Y-DDR | Y-DDR |
| Serial interface | 2-55Mbps | 2-55Mbps | 4 UART | 4 UART |
| SMBus interface | 2 | 2 | 2 | 2 |
| PCMCIA | Y | Y | Y | Y |
| Gigabit Ethernet (10/100/1000Mbps) | 2 | 3 | 4 | 4 |
| PCI controller | Y | Y | Y PCI/PCI-X | Y PCI/PCI-X |
| Security engine | N | N | N | |
| High-speed I/O (HyperTransport) | 1 | 1 | 3 | 3 |
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