H8 Family

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H8 is the name of a large family of 8-bit and 16-bit microcontrollers made by Renesas Technology, originating in the early 1990s within Hitachi Semiconductor and still actively evolving as of 2006.

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 peripherals such as timers and serial ports, and amounts of ROM and Flash-Memory and RAM. Built in ROM and Flash-Memory tends to range from 16K to 1024KBytes, and RAM from 512 to 512KBytes.

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 modes. 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 compilers for the H8 family, and there is a complete GNU port, including a simulator. There are also various hardware emulators available.

H8S may be found in digital cameras, printer controllers, smart cards, and in various automotive subsystems. Also, the LEGO Mindstorms advanced robot toy/educational tool uses this architecture (a H8/300, to be specific).