The ZXMMC+ HomePage
29/08/2008 An USB interface for zxmmc+ has been developed by Pino Giaquinto.
It allows USB communication between a ZX-Spectrum and a Windows-based PC when a RS-232 port is not available. The author obtained an unique ID from the USB chip manufacturer for this device, so "ZXMMC+ COMx" will appear in Windows Device Manager.
Further information along with instructions and schematic are available on author's web site: http://www.webalice.it/pino.giaquinto/ (Italian)
EeePC running the ZX-Com program (see the software section) connected to a 48K ZX-Spectrum
The ZXMMC+ interface plugs into the edge connector of any ZX-Spectrum, is based on a Xilinx CPLD and is currently in production.
Technical specs:
The V1.1 pcb has been assembled and tested. Changes from V1.0 are listed here:
- The Clock signal
amplifier/cleaner is now on-board
- The Reset signal provided on
Edge Connector goes through a diode/resistor to prevent device latch-up
- A pullup resistor has been
added on the ROM chip select signal.
- Reset button moved closer to
the top side, to avoid mechanical problem with 48K+ and 128K machines
- Reset circuitry modified for
improved reliability on certain Spectrum models
The clock amplifier included on V1.1 still requires a little change: due to different placement of the comparator, which is now on the opposite side of pcb (while the patch pcb required by previous version was glued directly on top of cpld chip), a fast transistor with pullup should be added. Being a small change, this can be done without any patch pcb. The picture on the left shows the small 1/8W resistor and an additional sot23 transistor, below the cpld chip, on the lower right side of the pcb.
This VIDEO (warning: 27MB) shows the ZXMMC+ (V1.0) under test with a few ROMs and ResiDOS with an early bootrom release.
Pino Giaquinto, the designer of the USB adapter, is also willing to assemble zxmmc+ interfaces on demand.
Technical Description Hardware Details Software Schematic PCB Contact the Author