Tham khảo tài liệu 'open-source robotics and proces control cookbook edwards l 242p newnes elsevier 2005 part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 2 Figure 2-1 Top of PCM-5820 Figure 2-2 Bottom of PCM-5820 The major hardware features are as follows Microprocessor - National Semiconductor Geode6. The fastest flavor of this processor available on the 5820 is 300 MHz some other vendors offer 333 MHz products. Geode is a Pentium-ish CPU it is hard to establish an exact equivalent with an Intel CPU but the performance is something like an accelerated Pentium 1. It supports the MMX-1 instruction set extensions but it lacks some Pentium core components such as MTRRs Memory Type Range Registers . Geode has an architectural equivalent ARRs Address Range Registers . It also has an extensive system of software traps that allow it to emulate many standard PC hardware features in firmware more on this topic later. Very roughly speaking a 300 MHz Geode is comparable in performance to a 200 MHz Pentium with MMX. Archaeologically Geode is descended directly from the Cyrix MediaGX processor. It appears to share some history with the early IBM Cyrix 486SLC clock-multiplied 486-compatible in an i386SX pinout and Blue Lightning clock-multiplied 486-compatible in an i386DX pinout processors. Because of the slightly unusual architecture there are some behavioral oddities in the Geode platform we ll discuss most of these in the text to follow. 6 The Geode range of x86-compatible Internet appliance processors was sold by National Semiconductor to AMD in a deal announced in mid-2003. However as at the time of writing I have yet to see an AMD-branded Geode chip. 28 Microcontrollers Single-Board Computers and Development Tools RAM - There is a single standard SODIMM slot supporting memory sizes up to 256 MB. The board uses unbuffered PC100 SDRAM. In our examples we will be assuming a system with 64 MB RAM. Ethernet - The board has a Realtek RTL8139 10 100 Ethernet MAC well-supported and relatively trouble-free. There is a network boot extension available in the system BIOS should you care to use it. USB - The system has .
