Not only does this design reduce the size of the programs, but since the CPU fetches instructions in 32-bit batches, two instructions can be retrieved in one cycle.
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These processors are part of the Hitachi SH7600 brand, a series designed for embedded systems featuring: This can achieve some degree of parallelism, albeit both sharing the same external bus (which can lead to congestion). While both physically identical, they are placed in a master-slave state, where the first one may send commands to the second one. This console has not one but two Hitachi SH-2 CPUs running at ~28.63 MHz each. Having explained the origins, let’s take a look at the shipped product. Upon hearing that, Sega decided on a two-chip configuration for the Sega Saturn. During the research phase of the SH, the team added minimal circuitry to allow the SH to work with other SHs within the same system at the same time. Luckily, Hitachi had another trick up in their sleeve, multiprocessing. So, they asked Hitachi to step up the clock frequency of the SH-2 - an impossible task once the chip is already out for manufacturing. Thus, Hitachi synthesised a second revision with a larger multiplier unit and other requirements on Sega’s checklist, leading to a new CPU called SH-2.Įven so, Sega couldn’t stand still after hearing what choice of CPU its competitors went for. Hitachi’s new creation implemented modern arts such as a RISC instruction set and a pipelined data-path, however, Sega wasn’t satisfied by the final product, especially due to the small 16-bit multiplier. In the end, the company chose a fresh CPU whose creator was desperately looking for an adopter, the Hitachi SuperH or ‘SH’. Just like its close competitors drowned with options during the RISC fever, Sega had to go through all the conundrums of choosing a vendor that could bring up the next generation of games (including those with ‘3D’ capabilities). Hopefully, the result didn’t get out of hand! Just in case developers want the extra dimension, Sega adapted some bits of the hardware to enable polygon drawing as well. Sega enjoyed quite a success with the Megadrive so there’s no reason to force developers to write 3D games right now. Remaining RAM chips are fitted on the back Motherboard with important parts labelled Diagram Main architecture diagram Showing 'VA8' revision which includes all components in a single board
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