Apple II SCSI Card

The Apple II SCSI Card project was the first experience Henry of ReActiveMicro had with CPLDs and VHDL coding back in mid 2006. The project however was never completed.

History

The idea behind the project was to learn more about PLDs and how they worked. The Apple II SCSI Card had two PALs on it. Henry was able to successfully extract coding from them as they were unsecured. The made the project possible as protected PALs would have posed a possible barrier.

The Apple II SCSI Card project also marks the first time Henry outsourced work. He had a programmer layout the PCB and code for the CPLD. The programmer however didn't understand some basic issues, such as why the board used line drivers such as an 74LS245. He also didn't know the Apple II or 65C02. Henry didn't know VHDL. Dealing with issues was going to be a problem Henry later discovered when things didn't work. Henry also lacked basic tools, such as a Logic Analyzer, which would have helped in diagnosing issues.

After many attempts to debug the coding and issues Henry gave up. He learned a lot from the project, which was the goal. It also was the reason he expanded the ReActievMicro shop with all the tools they use today.

At some point Henry would like to return to the project just to complete it. There is little demand of course for old, slow, SCSI Controllers.

Pictures

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  Apple II SCSI and Cable.

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  Apple II SCSI with dime for scale.

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  Apple II SCSI with CPLD.