The 68HC08 (also abbreviated as HC08) is a broad family of

8-bit In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data bu ...

microcontroller A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...

s from

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...

Semiconductor (later from

Freescale Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, embedde ...

then NXP). HC08's are fully code-compatible with their predecessors, the

Motorola 68HC05 The 68HC05 (also abbreviated as HC05) is a broad family of 8-bit microcontrollers from Motorola, Motorola Semiconductor (later Freescale Semiconductor, Freescale then NXP Semiconductors, NXP). Like all Motorola processors that share lineage from ...

. Like all Motorola processors that share lineage from the 6800, they use the

von Neumann architecture The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on the '' First Draft of a Report on the EDVAC'', written by John von Neumann in 1945, describing designs discus ...

as well as memory-mapped I/O. This family has five CPU

register Register or registration may refer to: Arts, entertainment, and media Music * Register (music), the relative "height" or range of a note, melody, part, instrument, etc. * ''Register'', a 2017 album by Travis Miller * Registration (organ), ...

s that are not part of the memory. One 8-bit accumulator A, a 16-bit

index register An index register in a computer's central processing unit, CPU is a processor register (or an assigned memory location) used for pointing to operand addresses during the run of a program. It is useful for stepping through String (computer science ...

H:X, a 16-bit

stack pointer A stack register is a computer central processor register whose purpose is to keep track of a call stack. On an accumulator-based architecture machine, this may be a dedicated register. On a machine with multiple general-purpose registers, it m ...

SP, a 16-bit

program counter The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, ...

PC, and an 8-bit

condition code register A status register, flag register, or condition code register (CCR) is a collection of status flag bits for a processor. Examples of such registers include FLAGS register in the x86 architecture, flags in the program status word (PSW) register in ...

CCR. Some instructions refer to the different bytes in the H:X index register independently. Among the HC08's there are dozens of processor families, each targeted to different embedded applications. Features and capabilities vary widely, from 8 to 64-pin processors, from LIN connectivity to

USB Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

1.1. A typical and general purpose device from the HC08 family of units is the microcontrolle
M68HC908GP32
The Freescale RS08 core is a simplified, "reduced-resource" version of the HC08. The Freescale HCS08 core is the next generation of the same processors.

External links

M68HC08 Family Reference Manual
- archive.org
HC08 Processor Families

Helium Open-Source RTOS for HCS08 MCUs

Digital Core Design 68HC08 - HDL IP Core

Example assembly language code written for ASM8

Educational material for the HC08
Motorola microcontrollers Freescale Semiconductor microcontrollers {{electronics-stub