The eZ80 Zilog CPU is an updated version of Z80 CPU. It comes in a few variations with many on chip facilities in addition to the basic CPU, such as flash ROM, RAM, GPIO and other IO services.

What is the eZ80 CPU

The eZ80 CPU is an enhanced version of the original Z80, largely maintaining compatibility with its predecessor while offering significant improvements. It can directly address up to 16MB of memory and achieves far greater performance per clock cycle due to increased instruction efficiency and pipelining. Additionally, it integrates various on-chip peripherals such as timers, UART, SPI, I2C, and GPIOs, reducing the need for external hardware components.

While the eZ80 might appear slow and limited by today’s standards, it represents, I think, an interesting evolution from the original 1970s Z80 to the modern day embedded microcontrollers.

See the Wikipedia page for basic overview of the CPU (https://en.wikipedia.org/wiki/Zilog_eZ80)

Key features of the eZ80 for RC

• Compatibility with many existing RCBus and RC2014™ retro modules.
• A fun DIY kit that can be assembled by anyone with basic soldering skills.
• Works in conjunction with RomWBW/HBIOS ensuring a high degree of compatibility with existing OS and applications (HBIOS, CP/M, BASIC, etc).
• Lots of potential for to do your own hacking and tinkering with the eZ80
• eZ80 CPU Module supplied with the eZ80 and other SMD components already soldered.

What’s included in the kit

The full kits includes everything you need. Including the PCBs, capacitors, IC sockets, connectors, and the various ICs. The included Programmable Logic Device (PLD) will also be flashed with the required logic.

The eZ80 CPU module will come with all the surface mounted components soldered. You just need to solder the PCB pins and a standard 6 pin programming header.

A 20Mhz and an optional 25Mhz crystal to allow you to ‘overclock’ your eZ80.

What else is needed

This kit is designed for RCBus and RC2014™

• A compatible RCBus or RC2014™ backplane
• recommended full 80 lane backplane
• A external RAM/ROM Module. These 2 modules have been tested and verified:
• RC2014 512K RAM/ROM module, or
• SC714 – RCBus Z80 Memory Module

• As per other serial RC2014™ modules, you will need a means to connect the eZ80's UART to a terminal emulator. The typical FTDI USB converters connected to your PC over USB should suffice.

• An eZ80 configured build of RomWBW flashed to the ROM of the external RAM/ROM Module.

Full details of the kit and assembly notes can be found at https://www.dinoboards.com.au/ez80-for-rc

Caveats

• Only a limited number of RCBus/RC2014™ modules have been tested to date. (Please see my project development journal describing the progress with porting and testing of various modules.)
• The ez80's SPI interface has no software support nor has it been tested yet.
• The I2C interface has limited software support at this stage.
• The onboard battery for the RTC seems to drain within a 1 or 2 month period.

Disclaimer

Please note that this is a kit, produced by a non-expert (me) for hackers, DIYers' and retro lovers, to tinker with. Please exercise caution and follow good safety practices. You will be working with sharp knives, a hot soldering iron, and small metal components. Be mindful of the risks involved in the build process. I will do my best to answer any questions you may have.

This kit is provided as-is, with no guarantees or warranties. By assembling and using this kit, you acknowledge that you do so at your own risk. The creator cannot be held responsible for any damage, injury, or loss that may occur during the assembly or operation of this kit.