H8 Family
Encyclopedia
H8 is the name of a large family of 8-bit
and 16-bit
microcontroller
s made by Renesas Technology, originating in the early 1990s within Hitachi Semiconductor
and still actively evolving as of 2006. The family also evolved into the higher performance SuperH
family of 32-bit microcontrollers.
Subfamilies include the H8/300, H8/300H, H8/500, H8S and H8SX series, each with dozens of different parts, varying by speed, selection of built in peripheral
s such as timers and serial port
s, and amounts of ROM
and Flash-Memory
and RAM. Built in ROM and Flash-Memory tends to range from 16 kB
to 1024 kB, and RAM from 512 B
to 512 kB.
The basic architecture of the H8 is patterned after the DEC
PDP-11
, with eight 16-bit registers
(the H8/300H and H8S have an additional bank of eight 16-bit registers), and a variety of addressing mode
s. Both H8/300H and H8S have eight 32-bit
registers, each of which can be treated as one 32-bit register, two 16-bit registers, or two 8-bit registers. Several companies provide compiler
s for the H8 family, and there is a complete GCC
port, including a simulator
. There are also various hardware emulator
s available.
H8S may be found in digital camera
s, some Thinkpad
notebooks, printer
controllers, smart card
s, chess computers, and in various automotive
subsystems. Also, the LEGO Mindstorms
advanced robot toy/educational tool uses this architecture (a H8/300, to be specific). Namco
employed an H8/3002 as a sound processor for various games it made in the late 1990s: notably those using its System 12
architecture.
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
and 16-bit
16-bit
-16-bit architecture:The HP BPC, introduced in 1975, was the world's first 16-bit microprocessor. Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816. The Intel 8088 was program-compatible with the Intel 8086, and was 16-bit in that its registers were 16...
microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
s made by Renesas Technology, originating in the early 1990s within Hitachi Semiconductor
Hitachi, Ltd.
is a Japanese multinational conglomerate headquartered in Marunouchi 1-chome, Chiyoda, Tokyo, Japan. The company is the parent of the Hitachi Group as part of the larger DKB Group companies...
and still actively evolving as of 2006. The family also evolved into the higher performance SuperH
SuperH
SuperH is a 32-bit reduced instruction set computer instruction set architecture developed by Hitachi. It is implemented by microcontrollers and microprocessors for embedded systems....
family of 32-bit microcontrollers.
Subfamilies include the H8/300, H8/300H, H8/500, H8S and H8SX series, each with dozens of different parts, varying by speed, selection of built in peripheral
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....
s such as timers and serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...
s, and amounts of ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
and Flash-Memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
and RAM. Built in ROM and Flash-Memory tends to range from 16 kB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
to 1024 kB, and RAM from 512 B
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
to 512 kB.
The basic architecture of the H8 is patterned after the DEC
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
, with eight 16-bit registers
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
(the H8/300H and H8S have an additional bank of eight 16-bit registers), and a variety of addressing mode
Addressing mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit designs. The various addressing modes that are defined in a given instruction set architecture define how machine language instructions in that architecture identify the operand of each instruction...
s. Both H8/300H and H8S have eight 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
registers, each of which can be treated as one 32-bit register, two 16-bit registers, or two 8-bit registers. Several companies provide compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
s for the H8 family, and there is a complete GCC
GNU Compiler Collection
The GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
port, including a simulator
Instruction Set Simulator
An instruction set simulator is a simulation model, usually coded in a high-level programming language, which mimics the behavior of a mainframe or microprocessor by "reading" instructions and maintaining internal variables which represent the processor's registers.Instruction simulation is a...
. There are also various hardware emulator
In-circuit emulator
An in-circuit emulator is a hardware device used to debug the software of an embedded system. It was historically in the form of bond-out processor which has many internal signals brought out for the purpose of debugging...
s available.
H8S may be found in digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s, some Thinkpad
ThinkPad
ThinkPad is line of laptop computers originally sold by IBM but now produced by Lenovo. They are known for their boxy black design, which was modeled after a traditional Japanese lunchbox...
notebooks, printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
controllers, smart card
Smart card
A smart card, chip card, or integrated circuit card , is any pocket-sized card with embedded integrated circuits. A smart card or microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally polyvinyl chloride, but sometimes acrylonitrile...
s, chess computers, and in various automotive
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
subsystems. Also, the LEGO Mindstorms
Lego Mindstorms
The LEGO Mindstorm series of kits contain software and hardware to create small, customizable and programmable robots. They include a programmable 'Brick' computer that controls the system, a set of modular sensors and motors, and LEGO parts from the Technics line to create the mechanical...
advanced robot toy/educational tool uses this architecture (a H8/300, to be specific). Namco
Namco
is a Japanese corporation best known as a former video game developer and publisher. Following a merger with Bandai in September 2005, the two companies' game production assets were spun off into Namco Bandai Games on March 31, 2006. Namco Ltd. was re-established to continue domestic operation of...
employed an H8/3002 as a sound processor for various games it made in the late 1990s: notably those using its System 12
Namco System 12
The Namco System 12 is an arcade system board released by Namco in late 1996. In hardware, it is an upgrade from Sony's PlayStation-based System 11, the MIPS R3000A microprocessor is 50% faster, and the C76 sound processor is replaced by the H8/3002...
architecture.