Template:mpu The CN3840-400 EXP is a 64-bit octa-core MIPS communication microprocessor designed by Cavium and introduced in 2005. This processor, which incorporates eight cnMIPS cores, operates at 400 MHz. This processor includes a number of hardware networking accelerators including units for high-performance packet I/O processing, QoS, TCP, and RegEx. This MPU supports up to 16 GiB of DDR2-800 ECC memory.

Cache

Main article: cnMIPS § Cache

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Cache Organization Cache is a hardware component containing a relatively small and extremely fast memory designed to speed up the performance of a CPU by preparing ahead of time the data it needs to read from a relatively slower medium such as main memory. The organization and amount of cache can have a large impact on the performance, power consumption, die size, and consequently cost of the IC. Cache is specified by its size, number of sets, associativity, block size, sub-block size, and fetch and write-back policies. Note: All units are in kibibytes and mebibytes.

L1$ 320 KiB 327,680 B 0.313 MiB L1I$ 256 KiB 262,144 B 0.25 MiB 8x32 KiB 64-way set associative   L1D$ 64 KiB 65,536 B 0.0625 MiB 8x8 KiB 64-way set associative Write-through L2$ 1 MiB 1,024 KiB 1,048,576 B 9.765625e-4 GiB     1x1 MiB 8-way set associative

Memory controller

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	Integrated Memory Controller
	Max Type DDR2-800 Supports ECC Yes Max Mem 16 GiB Controllers 1 Channels 1 Width 128 bit Max Bandwidth 11.92 GiB/s 12,206.08 MiB/s 12.799 GB/s 12,799.003 MB/s 0.0116 TiB/s 0.0128 TB/s Bandwidth Single 11.92 GiB/s

Expansions

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	Expansion Options
	PCI-X Width 64 bit Clock 133.33 MHz Rate 1,017.25 MiB/s Features host or slave UART Ports 2 GP I/O Yes

Networking

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	Networking
	MII RGMII Yes (Ports: 8) SPI SPI-4.2 Yes (Ports: 2)

Hardware Accelerators

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	Hardware Accelerators
	RegEx RegEx Yes Features 16 Engines Networking TCP Yes QoS Yes Compression Compression Yes Decompression Yes

Block diagram

Datasheet

• OCTEON CN38XX/CN36XX 4 to 16-Core Product Brief