Port 是 Pin 的集合。由 Port 讀入資料，其中的 bit 代表 Pin 腳。
What is an input/output port?
較符合目前定義
Difference between reading PORT and PIN
Building a computer around a 6502 processor
Assembly In One Step
圖解6502 指令集
6502.org
have info on new CPU in HP12C Platinum...
Reverse Engineering the MOS 6502 CPU [video]
外部連結
6502 軟體、硬體及應用 - 陳金追 松崗
6502汇编语言程序设计(1版)
6502汇编语言程序设计(2版)之前言
6502 PRIMER: Building your own 6502 computer
Rockwell 6502 Programmers Reference
Atari 2600 Programming Tutorial
ASSEMBLY LANGUAGE PROGRAMMING FOR THE ATARI COMPUTERS
6502 Assembly Language Programming
6502.org