2MB Fast RAM for ozRaptor (fully assembled)

Description

An alternative to the RCBus 2MB linear memory module, this module uses a specially designed interface to allow for high speed memory operation. Break the 64K barrier with this high speed memory module designed for the ozRaptor module

The ozRaptor module can supports up to two of these modules, to allow for up to 4MB of linear direct access 0 wait state memory.

Fully assembled and tested module, ready to be inserted into a ozRaptor baseplane.

Click here to view the kit version of this module.

General Description

A key feature of the eZ80 CPU is its 24bit addressing capability allowing programs to be written that can utilise up to 16MB of memory natively. No paging or banking hardware needed. No need for applications to be developed that limit themselves to 64K or complex paging mechanisms.

Unlike standard Z80 memory modules that only work with a 16-bit address, the Fast 2MB Linear RAM module is specifically designed to take full advantage of the eZ80’s 24-bit address space. It provides a continuous 2MB block of memory that can be directly accessed by the eZ80, making it possible to build or port larger programs.

Key features

• Supports up to 4 512K SRAM chips.
• Operates at 0 cycle wait states to achieve maximum performance of your eZ80 system.

What is the Green Series of Retro Kits

The Green Series of kits are designed around the RCBus/RC2014 bus, powered by an eZ80 CPU (as apposed to the Z80 CPU), and are broadly compatible with many RC2014 and RCBus kits and CP/M and RomWBW software stacks.

For more information of the eZ80 CPU, see the Green Series overview.

Other technical notes

• The 2MB Linear memory module is only active when the eZ80’s Chip Select 1 (CS1) is asserted
• The modules memory address range can be configured for operating at: 0x400000 to 0x5FFFFF or 0x600000 to 0x7FFFFF.
• The timing can be viewed and changed with the EZ80.COM CP/M program.

Software Status

There are currently a number of software projects under development to take advantage of this memory module.

• A port of BBC-BASIC* (version 5) for development of BASIC programs https://codeberg.org/dinoboards/eZ80-for-rc-basic.
• A port of Clang* (with associated c runtime) for building C and Assembly language programs https://codeberg.org/dinoboards/ez80-clang.
• EZ80.COM – a CP/M program to allow for managing and testing the extended memory.
• EXE.COM – a program for loading and executing programs in the extended memory.

* These languages enable the writing of application to take full advantage of the extended memory module. The ports are still under active development. See their respective repos for details of porting progress.

• The EXE.COM allow execution of CP/M programs running in the extended address space – with the CLang runtime support to marshall all the CP/M operations to the 64K page.
• The CLang port still requires the 64K paged memory module (512K ROM/RAM) module with RomWBW and CP/M installed.

Although it may be possible to use the official Zilog ZDS II development studio to create your own ‘applications’ – this is not a recommended approach.

What’s included?

This module has been fully assembled and tested by me.

What else do I need to make this work?

• a ozRaptor with required RCBus modules.