N.B. Due to the current USA tariffs on Canadian goods (35% & 50%) plus significant extra brokerage fees and paperwork, I will NOT be accepting orders for shipment to the USA.

This system is functionally the same as the eZ-Tiny system but in an RCBus 1.1 inch "Small" form factor plus the inclusion of a QWIIC connector for I2C peripheral expansion. As shipped, it has an embedded CP/M 2.2 system but the buyer could change that to CP/M-3 or MP/M if they choose to update the BIOS.

One very noteworthy feature is that it can function either as a standalone eZ80 system like the eZ-Tiny or as an RCBus card. Since it already contains memory, serial ports and "disks", the RCBus usage would be more like an SBC (Single Board Computer) with I/O expansion via the RCBus.

The Standalone mode has been verified to work in a manner similar to the eZ-Tiny. At this time the RCBus environment has not been tested but it was designed around the V1.0 RCBus Specification and the circuit diagram is included.

Features:

• Zilog eZ80F92 or eZ80F93 at 18.432 MHz
• 512KB or 2MB of zero-wait SRAM
• Two serial ports via USB or RCBus signals with a default of 8,N,1 at 230400 baud
  • A serial-to-USB bridge & connector is included on board
• A microSD push-push socket with SPI interface at ~3MHz
• 8MB of serial flash as a resident flash "disk"
• 2KB of I2C EEPROM available for user programs
• A QWIIC header for external I2C boards
• A Real Time Clock (RTC) with rechargeable battery
• A RUN (green) / HALT (red) bicolour LED
• A user-programmable LED
• A RESET pushbutton
• An optional ZDI debug header
• USB or RCBus powered

Included Items:

• An assembled and tested system as described above and similar to the one pictured.

• A 16GB or larger microSD card and adapter with an 8MB CP/M partition and a FAT32 partition with documentation including the BIOS & CP/M source code plus schematic & datasheets and approximately 7.5GB or more of CP/M-era software including various application programs, CPMUG, Dr. Dobbs Journal, SIG/M, The Computer Journal, etc.

Required Items:

• When used in an RCBus system it will obviously require a backplane. Serial communication to a console can then be either via the RCBus RX & TX signals to another RCBus card or via USB to a host computer. If a backplane is used without USB then the system will also require a backplane power supply.

• When using a USB console or just as a standalone system, it will require a host computer with a USB port plus a Mini-B cable or adapter and a terminal emulation program such as HyperTerm or TeraTerm. Also required is the Silicon Labs USB to UART VCP (Virtual COM Port) driver which should be automatically installed by Windows or is downloadable from their website with versions also available for Linux, Android etc.

Disclaimer:

• These systems and their software are for hobbyist use only. They have been assembled on a reasonable efforts basis and are tested as working in standalone configuration before shipment.

• The seller is the original designer / builder of these systems and the author of the BIOS.