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A2DVI - Apple II Digital Video

This is a project for a digital DVI/HDMI Apple II video card. It directly produces a digital video stream from Apple II's memory content. The signal is output via an HDMI connector, connecting the Apple II to modern displays with HDMI (or DVI) inputs. No more analog signal conversion required.

The project is a collaboration with Thorsten Brehm. His related firmware project is here: https://github.com/ThorstenBr/A2DVI-Firmware

For the DVI output to be active, the new firmware developed by Thorsten should be used.

The card also has an alternative analog VGA connector. For the VGA output to be active, the VGA firmware developed by Mark Aikens should be used.

The card can produce either an analog VGA or a digital HDMI signal, but not both simultaneously. To switch between modes, a firmware update is required and opening/closing connections.

As of v2.0 VGA function is not supported - the card is DVI only. V2.2 has an onboard driver to invoke the configuation utility by PR#N, where N is the slot number.

Procedure to activate DVI mode

  • v1.2: program A2DVI-Firmware to RPI Pico; remove U6 and disconnect pins 11, 12 and 13 of U5.
  • v1.5: program A2DVI-Firmware to RPI Pico; open all 9 DIP switches.
  • v1.6: program A2DVI-Firmware to RPI Pico; desloder the 8 soldering pads at GPIOs 14-21.
  • v1.7: program A2DVI-Firmware to RPI Pico; desloder the 8 soldering pads at GPIOs 14-21; remove VGA sub-board and ribbon cable.
  • v2.0: program A2DVI-Firmware to RPI Pico.
  • v2.2: program A2DVI-Firmware to RPI Pico.

Procedure to activate VGA mode

  • v1.2: program VGA firmware to RPI Pico; replace U5 and U6.
  • v1.5: program VGA firmware to RPI Pico; close all 9 DIP switches.
  • v1.6: program VGA firmware to RPI Pico; sloder the 8 soldering pads at GPIOs 14-21.
  • v1.7: program VGA firmware to RPI Pico; sloder the 8 soldering pads at GPIOs 14-21; connect VGA sub-board to main board by the ribbon cable.
  • v2.0: N.A. - v2.0 is HDMI only.
  • v2.2: N.A. - v2.2 is HDMI only.

Dual-Language Support

The pin on the v1.5 and later boards is for AltChr connection, supported by A2DVI firmware for switching between alternative character sets on non-US versions of Apple II ("Euro-machines").

A2DVI PCB A2DVI PCB A2DVI PCB A2DVI PCB

Hardware

  • Based on the PICO controller board.
  • Provides a DVI video stream via an HDMI connector.
  • Low power/heat dissipation: less than 70mA@5V = 0.35W in operation.
  • Uses 4x 74LV245 bus transceivers for 5V/3.3V signal conversion of the Apple II bus.
  • Separate ALTCHR input pin for dual-language support: pin needs to be wired separately to the "language switch" of Euro-Apple IIs (optional).

Thanks

This is a project based on:

License

Board design by Ralle Palaveev (c) 2024.

All rights reserved.

Redistribution and use in source, binary, and manufactured forms, with or without modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code and design files must retain the above copyright notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary or manufactured form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  3. All advertising materials mentioning features or use of this software or hardware must display the following acknowledgement: This product includes software or hardware developed by Ralle Palaveev.
  4. Neither the name of Ralle Palaveev nor the names of its contributors may be used to endorse or promote products derived from this software or hardware without specific prior written permission.

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.