ZX-DOS

Introduction

The ZX-DOS is a FPGA-based hardware recreation of the ZX Spectrum, created by Villena. It builds upon the earlier work done by the ZX-UNO team.

The Next and ZX-DOS both use the Xilinx Spartan 6 XC6SLX16 FPGA, and both have multi-core capabilities. This makes the ZX-DOS an ideal candidate to run the Next core.

Hardware

The base model of ZX-DOS has 512MB SRAM, whereas the base Next specification requires a minimum of 1MB RAM. Therefore you should choose a 1MB ZX-DOS. The webshop is here, but currecnty only lists the 512MB model. We recommend emailing Antonio directly (info AT antoniovillena DOT es) to get pricing and availablity for the 1MB model.

If you already own a 512KB ZX-DOS, Antonio can supply a replacement 1MB hat which will enable you to use the Next core. Alternatively, Antonio can supply a full set of hats that can be used with certain models of Xilinx development boards.

You will also require a ps/2 keyboard, a VGA cable, a VGA monitor, and a micro SD card of at least 1MB capacity.

The ZX-DOS also supports a ps/2 mouse, and optional twin Atari-wired joysticks.

The ZX-DOS hardware does not include HDMI, RTC, ESP Wifi module or the Raspberry Pi Zero accelerator, so those features will be unavailable from the Next core.

Loading the Next Core Into Your ZX-DOS

1. Format a blank SD card.
2. Copy the latest Next distro onto the SD card.
3. Copy esxDOS 0.8.6 onto the SD card.
4. Edit NextZXOS/config.ini and change ps2=0.
5. Download https://github.com/zxdos/binaries/raw/master/zxnext_zxdos_issue2.ZX2 and rename to core31.zx2. Place it in root of SD. You may use a different slot number instead of 31, as long as you substitute your slot in the remaining steps of these instructions.
6. Boot into BIOS, which is power on (or CTRL+ALT+BACKSPACE), and press F2 on the first screen.
7. Use right cursor to go to Update menu.
8. Go down to core slot 31, and press ENTER.
9. Pick SD file. Answer "Yes" to the "Are you Sure?" question.
10. Wait. Type name "Next".
11. Exit/Save changes & Exit.
12. Boots straight into TBBLUE.FW and then NextZXOS, hopefully.

Notes

1. When in Next-land, CTRL+ALT+BACKSPACE doesn't get you back to DOS-land, so have to power off and on again to get back to the ZX-DOS boot menus.
2. There is no Reset or Drive button. All F keys work as expected.
3. No idea what the push button on the top of the DOS does.