The 68HC08 (HC08 in short) is a broad family of

8-bit In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...

microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...

s originally from Motorola Semiconductor, later from Freescale Semiconductor. HC08's are fully code-compatible with their predecessors, the

Motorola 68HC05 The 68HC05 (HC05 in short) is a broad family of 8-bit microcontrollers from Freescale Semiconductor (formerly Motorola Semiconductor). Like all Motorola processors that share lineage from the 6800, they use the von Neumann architecture as well ...

. Like all Motorola processors that share lineage from the 6800, they use the von Neumann architecture as well as memory-mapped I/O. This family has five CPU registers that are not part of the memory. One 8-bit accumulator A, a 16-bit index register H:X, a 16-bit stack pointer 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, is ...

PC, and an 8-bit condition code register 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 1.1. A typical and general purpose device from the HC08 family of units is the microcontrolle
M68HC908GP32
The

Freescale RS08 RS08 is a family of 8-bit microcontrollers by NXP Semiconductors. Originally released by Freescale in 2006, the RS08 architecture is a reduced-resource version of the Freescale MC68HCS08 central processing unit (CPU), a member of the 6800 micro ...

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