Overview of amb chip
Advanced memory buffer (amb) chip is a key chip used in server and high-performance computer memory system. In order to meet the ever-increasing performance and capacity requirements, the new generation of memory systems introduced a fully buffered dual in-line memory module (fb-dimm) architecture. This fb-dimm memory architecture takes the amb chip as the core, and communicates with the memory controller and other fb-dimm through high-speed, serial, point-to-point interfaces, and solves the problem of the traditional parallel memory architecture that is difficult to balance the speed and capacity. The performance of servers and high-performance computers has made a qualitative leap, but at the same time it has also brought about energy consumption issues. Since amb is one of the most power-consuming devices in the entire server, and the server has a great demand for amb (the number of amb is generally 16-32 times that of the processor), the power consumption of amb affects the server and even the entire computer data The power consumption of the center is very important: if the power consumption of amb is reduced a little, the power consumption of the server will be reduced exponentially, and vice versa. Because the technical threshold of amb chip design is relatively high, and low-power design is very difficult, there are very few ic design companies participating in the research and development of such products worldwide.
Arm chip product type
1. The arm7 series is optimized for low-power 32-bit cores for consumer applications sensitive to price and power consumption, including: embedded ice-rt Logic; very low power consumption; three-stage pipeline and von Neumann structure, providing 0.9mips/mhz. 2, securcore sc100 is specially designed for the security market, with specific features that resist tampering and anti-engineering. It also comes with a flexible protection unit to ensure the safety of the operating system and application data. 3, arm9 series Leading hard macro unit with high performance and low power consumption, with: 5-stage pipeline; Harvard structure provides 1.1mips/mhz. Arm920t and arm922t have built-in full-performance mmu, instruction and data cache and high-speed amba bus interface. The amba on-chip bus is an open standard and has become a de facto standard for soc construction and ip library development. amba's advanced high-performance bus (ahb) interface is now supported by all new arm cores, providing a fully integrated design system for development. Arm940t has built-in instruction and data cache, protection unit and high-speed amba bus interface. 4, arm9e series can be integrated processor, with dsp expansion and tightly coupled memory (tcm) interface, so that the memory runs at full processor speed, can be directly connected to the core. arm966e-s is used for real-time embedded applications where the size of the silicon chip is important, but the cache is not required. The tcm size can be configured: 0, 4k, 8k, 16k, and the maximum size is 64m. Arm946e-s has a built-in integrated protection unit to provide a real-time embedded operating system cache core solution. arm926et-s with jazelle expansion, separate instruction and data high-speed ahb interface and full performance mmu. The vfp9 vector floating-point integrated coprocessor further improves the performance of the arm9e processor and provides hardware support for floating-point operations. 5, arm10 series hard macro unit, with: 64-bit ahb instruction and data interface; 6-stage pipeline; 1.25mips/mhz; performance improved by 50% compared to the equivalent arm9 device. Two new advanced energy-saving methods have resulted in exceptionally low power consumption. The vfp10 coprocessor perfectly complies with arm10 devices to provide high-performance floating-point solutions.
A typical example of amb chip
In the fb-dimm system, there are two types of serial lines: one is the serial line responsible for data writing (called southbound, South zone), a serial line responsible for data reading (called northbound, north zone). These two serial lines are each responsible for the "pass-through" and "pass-through & merging" control logic in the amb chip. Among them, the data streams transmitted in the north and south areas are all in serial format, but the amb chip and the memory chip are still through the 64bit (note: the bit width is not fixed) parallel bus for data exchange, so the data between The serial-to-parallel format conversion is realized by the conversion logic in amb. At the same time, there is a data bus interface in amb, which is used to connect with the memory chip. Using the amb chip, which means that fb-dimm does not need to make changes to the existing dram chip, and the memory manufacturer can directly use the low-cost ddr2 chip. Although the use of a new type of buffer chip will increase some costs, it is much less expensive than making a brand-new ram chip.