Easy Z80 - Single Board Computer with RC2014 compatible bus

[Sergey Kiselev]

Easy Z80 project started when my son Max (15 years old) asked me what does it take to build a computer, and whether he can design and build one himself.

After some discussion and reviewing previous work, such as my Zeta SBC project, RetroBrew Computers ECB SBCs, RC2014, and considering other CPUs, we've settled on a Z80 CPU based self contained system, using Z80 peripherals, paged memory to support RomWBW and FUSIX, and 10 x 10 cm form factor (cheaply made by several PCB fabricators). We've also had decided to use SPLD (aka GAL) for chip selects, as it provides a gentle introduction into programmable logic, reduces the number of ICs, and allows re-configuring the I/O addresses and some other features.

Easy Z80 SBC specifications:

• Z80 CPU: Default clock frequency is 10 MHz. It is possible to run it on any other frequency as the CPU has a dedicated clock oscillator.
• Z80 SIO/0: Provides two serial ports. Two MAX232A transceivers are included on the board. TX and RX signals are 
  
• Z80 CTC: Timer interrupt and optionally baud rate generation for SIO
  
• 512 KB Flash ROM / 512 KB battery backed SRAM: The same paging mechanism as implemented in Zeta SBC V2 and in 512k ROM 512k RAM RC2014 Module.
  
• MAX693/ADM693 microprocessor supervisor: Reset generation, SRAM battery backup, power failure monitoring (and NMI), and an optional watchdog
  
• RC2014 compatible bus connector, including IEI/IEO signals
  
• Software: RomWBW 2.9.1 or newer, FUSIX
  
• Form Factor:10 cm x 10 cm board
• Open Source (GPL V3) design: https://github.com/skiselev/easy_z80/. You're welcome to make your own boards using provided KiCad and Gerber files, or make your own modifications to the project (as long as it follows GPL V3 license).

- Sergey

[TonyD]

It looks very impressive, well done !!

Tony