These systems were designed to be both small and fast Z80 compatible systems running CP/M 2.2 or one of it's derivatives. While they can be used as standalone systems, they do have an I/O expansion bus that allows the user to develop their own peripherals or use the IO2 demonstration board. Unlike many other Z180 systems, RTS/CTS handshaking has been implemented for the second serial port. After initialization, these systems run with ZERO memory wait states since each wait state would result in approximately a 25% reduction in effective speed.

This USB version with it's single cable and small size is an excellent candidate to use with the Java-based host CP/NET system as described at https://github.com/durgadas311/cpnet-z80 . Note that there is also a TTL/RS232 variant that is basically the same except for the power source and the serial interfaces.

Size: 2.18" x 1.98" (55.4mm x 50.2mm)

Features:

• Z8S180 at 33.333 MHz or 36.384 MHz
• 512 KB flash memory for the boot code, CP/M code and a 496 KB "disk"
• 512 KB zero-wait SRAM for CP/M and a 440 KB RAMdisk
• Two USB serial ports, both with RTS/CTS handshaking and a default of 115200 baud 8,N,1
• Two 16-bit timers
• Two DMA channels
• Bicolour red (halt) / green (run) LED
• I/O expansion via 0.1" headers
• Power via USB

Required:

• A USB to mini-B cable.
• A host with a USB port and a terminal emulator such as HyperTerm or TeraTerm plus the Silicon Labs USB to UART VCP (Virtual Com Port) driver which is automatically installed by Windows or downloadable from their website with versions for Linux, Android etc.

Assembly:

• There are a few SMD components and these come pre-installed on all boards. The remaining devices to be soldered are all through-hole components. Pre-built and tested systems are available for an additional cost.

Optional I/O Board:

An optional I/O board is also available. Since most components are SMD, these boards are only being offered in pre-assembled and tested form. This board has the following devices and features:

• A microSD socket with a 25 MHz byte-wide SPI interface
• An 8 MB parallel flash "disk"
• A battery-backed real time clock (RTC) - CR1220/CR1225 battery not included due to lithium shipping issues
• An 8-position DIP switch input port
• Two hex LEDs (byte wide display) with addressable decimal point LEDs
• A 16GB 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 of CP/M-era software including various application programs, CPMUG, Dr. Dobbs Journal, SIG/M, The Computer Journal, etc.

N.B. The processsor, CPLD and hex LEDs may be "used" due to the current supply chain issues. However all previously used devices are tested before shipment and processors are verified to work reliably at 36.864 MHz and 230400 baud.

If the I/O board which includes an SD card is not purchased, the base flash memory will have a .ZIP file with the BIOS source. There is also an option to purchase a USB "thumb" drive with the same data that is on an SD card.

Shipping and handling:

• Shipping is via Canada Post and includes tracked airmail within North America or NON-TRACKED airmail outside North America. Tracking outside North America is an optional extra and if the purchaser doesn't choose it, they accept the liability for any lost packages. Any taxes and/or duties are the responsibility of the purchaser.

Disclaimer:

• This system and it's software are for hobbyist use only. It has been assembled on a reasonable efforts basis and pre-assembled boards are tested as working before shipment.

The seller is the original designer / builder of the system and the author of the BIOS.