Mbps, Gbps: 一百万比特每秒，十亿比特每秒
skew：时间偏差，A比B快/慢一秒，就叫skew一秒
PCB：印刷电路板，也就是大多数电路板
IO： 输入输出电路
cable： 线缆
SerDes：串行转并行，并行转串行
# CPU
CU：Control Unit. send need-clac-data -> ALU clac -> get result send back -> to save in memory
ALU：Arithmetic Logic Unit. Binary clac, such as add/sub/mult(except interger division)
MMU：Memory Management Unit. registers like: MAR MDR PC AC CIR
- MAR. Memory adress register. save will-be-visited-data 's address
- MDR. Memory data register. saveor will-write-in-RAM data or from-RAM-data
- PC. Program Counter. save next-exe-instruction 's address
- AC. Accumulator. save ALU and CU 's middle-result data
- CIR. Current Instruction Register. save current executing instruction
RAM："random access memory"
ROM： "read-only memory"
PCI-E：计算机内部的一种高速总线
USB：通用串行总线 Universal Serial Bus
SPI：串行外设接口 Serial Peripheral Interface
I2C：双向同步串行总线 Inter Intergrated CirCUIT bus 内部集成电路总线
GPIO：通用输入输出/总线扩展器
UART：通用异步收发传输器(协议)
RS232：rs232物理层(接口标准)
JTAG：联合测试工作组
openOCD ：开源片上调试器(rear end)
GDB：GNU调试器(front end)，主要调试c/c++程序