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Type Name Latest commit message Commit time 2000EATX-KiCAD-R12 Add files via upload Jul 22, 2021 Amiga-KiCad Added Agnus 8375 Jul 16, 2021 BOM Add files via upload Jun 26, 2021 DataSheets Add files via upload Jul 15, 2021 Images Add files via upload Jul 22, 2021 STL Add files via upload Jun 26, 2021 AssemblyNotes.md Update AssemblyNotes.md Jul 20, 2021 LICENSE Initial commit Mar 13, 2021 PCB.md Update PCB.md May 4, 2021 README.md Update README.md Jul 22, 2021 userguide.md Update userguide.md Jul 15, 2021 View code [ ] Amiga 2000 EATX PCB Project Status Project Goals User Guide and Considerations Ordering PCBs BOM and Assembling the Amiga 2000 EATX PCB Changes from the original Amiga 2000 Video Memory Audio Output Disk Drive Support ISA Slots Serial Port PCB Layout ATX Power External Reset Switch Real Time Clock What has not changed? Most External Ports Zorro II Slots Kickstart ROM Everything Else Revision History Acknowledgments README.md Amiga 2000 EATX PCB The purpose of this project is to develop an open source Amiga 2000 PCB in the EATX form factor. What is EATX? It is an ATX variant that allows slightly deeper PCBs, measuring 12 x 13 inches (305 x 330 mm). These are referred to as Extended ATX, or, EATX (see Enterprise Electronics Bay Specification). The length of Zorro II cards and the abundance of components on the Amiga 2000 makes EATX the best choice for this project. There are one-to-one board replacement projects for the Amiga 2000, but none to change the layout to meet current form factor standards. In addition, the Amiga 2000 made use of connectors and custom parts that are no longer commercially manufactured. This often requires parts to be pulled from existing machines. As such, this project will make use of only actively supported components when possible. In addition to a new board replacement option, I believe the ubiquitous EATX standard will bring additional interest to the Amiga as a hobbyist and retro-computing option. At the time or writting this, the Amiga operating system is still actively developed and supported. In addition, there is a substantial database of existing software and hardware add-on options and a very active community. [REV12] Project Status July 21, 2021 Revision 1.2 is the production candidate. I am currently running a Supra Wordsync SCSI card, a Commodore A2630 accelerator, and a Pi HDMI video card on the Amiga 2000 EATX. AIBB can be seen on the screen. I allowed the Amiga 2000 EATX to run for several hours playing games and running memory tests without issue. All the external ports are working as expected. [aibb] Project Goals 1. Enter Amiga 2000 Rev 6.2 schematics into KiCad, including all known A2000 Rev 6.x PCB updates. 2. When possible, replace end of life components with suitable alternatives that are commercially available. 3. Layout and route components using the EATX standard as a guide. 4. Test it and make sure it works. User Guide and Considerations Review this information to ensure a smooth and happy experience when assembling an Amiga 2000 EATX system. It will answer many questions and inform you as to the physical requirements of the Amiga 2000 EATX PCB, various Amiga plug in cards, etc. Ordering PCBs See information here. BOM and Assembling the Amiga 2000 EATX PCB See information here. Changes from the original Amiga 2000 Video The DB23 video connector has been removed in favor of the HD15 connector. One of the goals of this project is to avoid parts that are not commercially available. The D-Sub 23 connector is a prime example. They are not stocked at popular electronic supply houses. Thus, the change to the widely available HD15 connector. Analog red, green, blue, HSYNC or COMPSYNC (jumper selectable), and VSYNC are supplied using the VGA standard pin out configuration. Other external video port signals are not supplied. Any VGA cable can be used to supply the video signal to a VGA monitor or conversion box supporting the 15KHz standard. The internal video slot is complete with all signals. The external composite video jack has been removed. Memory The original 256Kx4 DRAMs have been replaced by a single SRAM. The 2000 EATX is permanently configured to recognize 1MB chip ram and requires Fatter Agnus (MOS 8372A). Other Agnus revisions are not supported at this time. Audio Output The left/right RCA jacks of the Amiga have been replaced by a 3.5mm stereo audio jack. Disk Drive Support Internally, any Amiga compatable double density disk drive or properly configured Gotek floppy emulator is supported. Up to two internal disk drives may be connected to the internal floppy connector. The external disk drive port has been removed. ISA Slots The number of 16 bit ISA slots has been reduced to three. This was done to provide additional space on the board. Support for ISA cards via a Bridgeboard is unchanged from the Amiga 2000. Serial Port The internal (infernal) serial port has been removed. The external serial port is present with all signals. PCB Layout For obvious reasons, it was necessary to move components relative to one another. Zorro slots occupy slot positions 1-5, overlapping with ISA slots in the first 3 positions. The video slot occupies the sixth slot position on the board. The CPU slot occupies position 7. It is possible to have every slot position populated simultaneously. ATX Power ATX 24-pin power supplies are supported with -5V being supplied on board via a voltage regulator. The original Amiga 2000 power supply is not supported. External Reset Switch The computer can be reset via CTRL-Amiga-Amiga on an Amiga keyboard or via the reset switch found on EATX computer cases. Real Time Clock The real time clock (RTC) has been changed to the RTC-62423. This RTC has a built in crystal and does not need adjustment. In the Amiga, the RTC is written and read by 4 address and 4 data lines. Unfortunately, there are no direct "modern" replacements for this type of bus connected RTC. As such, this is among the legacy IC's that must be obtained. It is readily available where these type of legacy IC's are sold. What has not changed? Most External Ports The keyboard, joystick, mouse, parallel, and serial ports are all present and function as they did in the Amiga 2000. The parallel, serial, mouse, and joystick ports are stacked DB9 and DB25 connectors, respectively. The Amiga keyboard port remains a DIN5 connector. Zorro II Slots There are no changes to the Zorro II slots. Kickstart ROM For now, the Kickstart ROM remains the original 27C400. These are no longer made, but are easy to find. In addition, this allows the use of an original Commodore Kickstart mask ROM. Revision 1.2 added support for 1MB (27C800) and 2MB (27C160) EPROMs for custom Kickstart ROMs. Everything Else If something is not specifically mentioned, you should expect it to be unchanged in function or component from the original A2000. Revision History Rev 0 - Prototype board Rev 1.0 1. Adjusted postion of slots and several other components 2. Moved ATX On/Off circuit to back of board Rev 1.1 1. New ATX on/off circuit 2. Modified SRAM circuit 3. Added case fan header 4. Fixed U100 and other footprints 5. Moved some components 6. Cleaned up silk screen Rev 1.2 PRODUCTION CANDIDATE 1. Fixed traces on the keyboard connector (error on the C= schematic) 2. Added missing _COPCFG trace 3. Deleted some extra traces that were not needed 4. Added HSYNC/COMPSYNC selection jumper 5. Cleaned up parts of the schematics 6. Widened U801 footprint (RTC62423 is wider than the standard SOIC package) 7. Added support for 1 and 2 MB Kickstart ROMs (512k still supported) 8. Added some space around the external ports...they were crowded Acknowledgments kr239 - for the Amiga 500 DRAM replacement project inspiration and LIV2 and texneus for the modifications used in this project iansbremmer - Amiga IC KiCad footprints - https://github.com/ iansbremner/ReAmiga-3000---KiCAD texneus - ATX ON/OFF circuit DarrenHD - Pics and measurements of the Amiga 3000 video slot bracket adapter - https://eab.abime.net/showthread.php?t=106928 Chucky - Amiga Diagrom...a priceless diagnostic tool - http:// www.diagrom.com/ About Develop an Amiga 2000 PCB in the EATX form factor. 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