MB03+ Slim  is a powerful, compact, next-generation ZX Spectrum interface that provides the functionality of a large number of hardware and system add-ons for the ZX Spectrum and compatible computers, in an all-in-one solution. The MB03+ is normally connected to the standard edge connector of any ZX Spectrum. It consists of modern circuitry with a fast FPGA chip and is compatible with the popular divMMC/SD interface. 

Please visit my Facebook page at https://www.facebook.com/mb02plus/  and my Twitter page at https://twitter.com/LMN1282. You can also check and read more MB03+ related articles, reviews and discussions on the forums http://oldcomp.cz/viewforum.php?f=158 and  https://spectrumcomputing.co.uk/forums/viewtopic.php?t=4157 .

Jan Kucera aka LMN128/Czech Republic, author of the MB03+

The MB03+ is a non-profit, hobby-based development project. Support for users is available on the Telegram channel: t.me/eLeMeNt_forum

Specifications :

•     square shape 8x8cm board, connected to ZX edge socket in horizontal position

•     powered by ZX Spectrum - very efficient switch power supply

•     fully compatible with all original ZX Spectrum models

•     digital video and audio output to modern TVs or PC monitors, scan line display effects possible to mimic old good retro TV/CRT displays

•     FPGA - RetroCoreX board: Xilinx Artix7 - XC7A100T, the main brain of the machine

•     4MBytes SRAM + 2MBytes SRAM + 1MBytes FLASH + FRAM 8KB (system info, bios config);  RAM is expandable through expansion sockets

•     batteryless RealTimeClock (RTC72421)  for esxDOS SYS driver, synchronized by internet

•     Wi-Fi module ESP8266, UART connection

•     3x USB-C ports, one for a PC-link, second for PC keyboard or HUB and third for mouse (real USB HID devices)

•     Custom ROMs of 16KB and 64KB (DerbyPro), diagnostic and test ROMs, possibility to use patched ROMs, e.g. 64char ROM

•     tremendous sound capabilities: 3xAY/YM, TurboSound or TurboSound FM (2xYM2203), SAA1099, SounDrive/Stereo Covox/Specdrum, SID (C64) and General Sound (28 MHz Z80-CPU, 16KB ROM, 2MB RAM, 4x 8bit channels)

•     Z80 DMA and FastDMA, SafeNMI, SaveINT, I/O port-based LIFO stack and other internal hardware enhancements

•     Ultimate firmware - a quick boot and SetUp with easy hardware settings and switchable configurations

•     divSD, divMMC, Z-Controller SD, esxDOS (UnoDOS) compatible

•     TRDOS emulation via esxDOS, compatible with other systems like divide+ (G+DOS) 

•     TIMEX Hi-Color and Hi-Res graphics modes and ZX-Uno's Radastan graphics, ULAplus and TrueColour palettes

•     two VideoRAMs also on 48K Spectrums, three levels of non-flickering GigaScreen, Klayer mode with a transparence colour

•     attribute-based 512*192 HiResColour and HiResindeXedColour modes

•     HGFX - ZX Planar, HAM and FILL modes, resolutions: 256*192, 512*192, 512*384 and 720*546, up to 256 colours from 16777216

Basic comparation to MB03+ Ultimate:

•  modern USB support, more USB slots;  Ultimate: has only 1 USB slot and supports only old usb devices with ps/2 protocol

• i2c for addons via qwiic cable;  Ultimate: doesn't have it.

• swap-able RetroCoreX board;  Utimate: universal internal expansion connectors, FPGA is not upgradable

• ram: 4MB SRAM, 2MB GS, 1MB FLASH, but RAM is expandable;  Ultimate: 16MB SRAM, 2MB GS, 1MB FLASH

• no internal Matrix LED

• no battery for RTC

• no CF slot, no divIDE and no BSDOS

• no internal expansions