Freescale 68HC11

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Motorola MC68HC11 in a 48-pin dual in-line package (DIP)

The 68HC11 (6811 or HC11 for short) is an 8-bit microcontroller (µC) family introduced by Motorola in 1985.[1] Now produced by Freescale Semiconductor, it descended from the Motorola 6800 microprocessor. It is a CISC microcontroller. The 68HC11 devices are more powerful and more expensive than the 68HC08 microcontrollers, and are used in barcode readers, hotel card key writers, amateur robotics, and various other embedded systems. The MC68HC11A8 was the first MCU to include CMOS EEPROM.[2]


Motorola 68HC11 registers
Main registers
A B D register pair
Index registers
IX X index register
IY Y index register
SP Stack Pointer
Program counter
PC Program Counter
Status register
  1 1 H I N Z V C Flags

Internally, the HC11 instruction set is upward compatible with the 6800, with the addition of a Y index register. (Instructions using the Y register have opcodes prefixed with the byte 0x18). It has two eight-bit accumulators, A and B, two sixteen-bit index registers, X and Y, a condition code register, a 16-bit stack pointer, and a program counter. In addition, there is an 8 x 8-bit multiply (A x B), with full 16-bit result, and Fractional/Integer 16-bit by 16-bit Divide instructions. A range of 16-bit instructions treat the A and B registers as a combined 16-bit D register for comparison (X and Y registers may also be compared to 16-bit memory operands), addition, subtraction and shift operations, or can add the B accumulator to the X or Y index registers. Bit test operations have also been added, performing a logical AND function between operands, setting the correct conditions codes, but not modifying the operands.



In the early 1990s Motorola produced an evaluation board kit for the 68HC11 with several UARTs, RAM, and an EPROM. The cost of the evaluation kit was $68.11.[citation needed]


Other versions[edit]

The Freescale 68HC16 microcontroller family is intended as a 16-bit mostly software compatible upgrade of the 68HC11.

The Freescale 68HC12 microcontroller family is an enhanced 16-bit version of the 68HC11.

The Handy Board robotics controller by Fred Martin is based on the 68HC11.[3]



  1. ^ Hambley, Allan R.(1839). Electrical Engineering: Principles and Applications, Pearson Higher Education. p. 417. Digitized by Google. Retrieved on May 17, 2010.
  2. ^ M68HC11 Reference Manual
  3. ^ Handy Board Hardware

External links[edit]
