H8 Family

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Hitachi H8/323

The Hitachi H8 is a large family of 8-bit, 16-bit and 32-bit microcontrollers made by Renesas Technology, originating in the early 1990s within Hitachi Semiconductor. The original design, the H8/300, was an 8-bit processor that had a 16-bit registers and ALU that allowed some 16-bit operations. Two upgraded versions were introduced, the H8/300L that expanded the instructions to become a full 16-bit machine while being optimized for low cost, and the H8/300H which further expanded the registers to allow 32-bit operations and was optimized for low-power/high-performance roles. Many variations exist.

The entire line was sold to Renesas in 2003. Renesas continues to sell the designs as of 2023^[update], but only to existing customers. An administrator on the Renesas user community boards commented in 2011 that there are no plans for further development of H8 based products.^[1] H8 was supported in the Linux kernel starting with version 4.2 but support was removed in version 5.19.^[2]

For higher performance needs, Hitachi introduced their SuperH family of 32-bit RISC-like microcontrollers, which have largely replaced the H8.