6502 is one of the most famous series of low cost 8 bit CPU.  In 1970s, 6502 processors are regarded as VLSI which have about 4,000 transistors per chip. A 6502 processor is 8-bit processor. Since the manufacturing cost of the products using 6502 are low, this technology bought us the age of "Home Computer Revolution" in 1980s. 6502 home computers such as: Commodore RadioShack TRS-80, Commodore PET, Apple II, BBC Micro, Atari 800XL, etc were appeared in consumer market in 1980s.  Many people using 6502 home computers are now leaders in the IT industries.  One of the characteristics of 6502 processor is that it has only a few internal registers that allow addressing 64Kb of memory. The 6502 processor is also regarded as "Little Endian". "Little Endian" requires the representation of addresses of 6502 to be in the format of "least significant byte first". The 6502 instruction-set also included a set of binary coded decimal (BCD) instructions under the "Decimal Mode" of the 6502 processor.

 

The followings are some operation specification of a 6502 processor:

• Power supply of a 6502 processor: 5V 
• Clock speed of a 6502 processor: 1Mz or 2Mz
• A 6502 processor is compatible to bi-directional data bus
• A 6502 processor can select either external clock or "on-chip" clock
  
• Two on-chip clock option for a 6502 processor: 
  
• External Single clock input
  
• Crystal time base input
• Provides maskable and non-maskable interrupt for a normal 6502 processor

About the website of 6502 Assembly

This website not only provide the basic of programming 6502 Assembly, it also provides the background of 6502 Family microprocessor.  To learn the 6502 Assembly language, first of all, you should be familiarize the 6502 opcode. Here is some links for material related to studying the technology of 6502:

 

 

The followings are common 6502 Computers:

 

 

 

 

 

 

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