H8

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H8, a family of 8-bit microcontrollers, since the early 1990s developed and made by Hitachi, in April 2003 transferred to Renesas Technology. The chip consists of a CPU, various read only and  random access memory variations, including parallel and serial I/O-ports, AD-converter, and timer. The controller was used in several dedicated chess computers of the early 90s.

=Architecture= The basic architecture of the H8 was influenced by the DEC PDP-11, with sixteen 8-bit registers (R0H, R0L, ..., R7H, R7L), with some instructons also accessible as eight 16-bit registers (R0 - R7), where R7 is the stack pointer, 16-bit program counter, 8-bit condition code register (CCR) and a variety of addressing modes. Opposed to the PDP-11, H8 is a big-endian machine, since the upper 8 bits of a 16-bit word are stored at the even word address, the lower 8 bits at the odd address. The H8/300 has a concise set of 57 RISC-like instructions, 2 or 4 bytes long. Arithmetic, logic, shift and bit manipulation instructions are performed as register-to-register operations, or with immediate data.

=Manuals=
 * Hitachi Single-Chip Microcomputer H8/3297 Series Hardware Manual (pdf)
 * H8/300 Programming Manual (pdf)

=External Links=
 * H8 Family | Renesas Electronics
 * H8 Family from Wikipedia
 * H8/330 from Schachcomputer.info Wiki (German)
 * H8/300 Application Binary Interface for GCC - GNU Project, Free Software Foundation (FSF)

=References= Up one Level