Internal BlueSCSI for Apple IIgs and //e
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BlueGS: Internal BlueSCSI for Apple IIgs and Enhanced //e

https://github.com/xunker/blue-gs

About

BlueGS is the internal hard drive your Apple IIgs and //e always craved.

Using the BlueSCSI SCSI drive emulator and your compatible SCSI card, you have a fully internal hard drive with accessible microSD slot while still keeping your DB-25 connector free for other peripherals.

Close-up of BlueGS installed in IIgs slot BlueGS installed in IIgs slot, right side BlueGS installed in IIgs slot, left side

How it works

BlueGS connects between your SCSI card and its external DB-25 connector to give you a seamless installation. The BlueGS module itself mounts in a free DB-25 connector cutout in the rear of your IIgs or Enhanced //e.

Overhead view of BlueGS in IIgs slot Frontal view of BlueGS in IIgs slot

Features

  • Gives your Apple IIgs or //e an internal, cable-free hard drive
  • Can be powered from SCSI termination power only (if present)
  • "Termination Power" mod is not required (when powered from the IIgs internal fan connector)
  • Can provide termination power to the SCSI bus (when powered from the IIgs internal fan connector)
  • Built-in termination that is controlled with a single switch
  • TI/Unitrode termination ICs instead of passive termination, reduces power consumption by over 2/3rds
  • Connection for external drive activity LED

Compatible SCSI cards

Tested:

Untested, but expected to be compatible:

  • Apple Rev C SCSI and clones
  • Apple High-Speed SCSI ("Sandwich II")

Unknown, but likely compatible:

  • Ramfast SCSI
  • Any SCSI card that uses has the same IDC-26/DB-25 pinout as the Apple Rev C SCSI

If you have an SCSI card with an IDC-26/DB-25 connector that has not been tested and would be willing to test your card with BlueGS, please contact us to arrange to have a test unit sent to you.

Performance

Using BenchmarkD with Apple IIgs (ROM 1, "Fast" speed), GS-RAM Plus w/ 2MB, GGLabs A2SCSI card.

  • Read
    • File: 52 KB/s
    • Block-by-block: 36 KB/s
    • With 64K buffer: 79 KB/s
  • Write (File): 37 KB/s

Board

Rendering of front of board v1.2

Rendering of back of board v1.2

TBA

Assembly

Bill-of-Materials

See BOM.md.

Compatible Termination ICs

See TERMINATION.md.

Assembly Steps

MicroSD Slot

Switch

Set Jumpers

LEDs and Resistors

Termination ICs and Capacitors

Auxiliary +12V input regulator, diodes, and capacitor

SCSI Card connections

Blue Pill Module

Installation

Bracket

TBA

Cables

TBA

Auxiliary +12V connection

TBA

Slot Attachment

TBA

Usage

TBA

Schematics

V1.2 Schematic

V1.1 Schematic

EDA/Kicad Files

Kicad of current design can be found in kicad directory.

Version Changes

See CHANGES.md.

Credits

This project would not be possible without the work done by ztto, Tambo, Eric Helgeson, and many others.

The "Blue Pill" footprint was originally created by Yet-Another-Average-Joe.

Symbol and footprint for Molex 105162-0001 MicroSD slot created by SnapEDA user HMantz.

External LED driver circuit credit to @akuker on Open Retro SCSI Discord.

License

See LICENSE.md.