Characterising Am9511A-1 APU

I’ve built two hardware solutions supporting the AM9511A APU. Partly for historical enjoyment, and partly because the AM9511A is actually still faster at floating point and 32-bit long arithmetic than “modern” Z80 devices. I’ve built a Z180 based board, the YAZ180, which runs the AM9511A at 2.304MHz. And I’ve built an APU Module for the […]

CP/M-IDE for RC2014

Just over 4 years ago, on 18th March 2018, I committed the first CP/M-IDE files into the RC2014 repository. Now that some time has passed and it has developed into a stable solution for CP/M I think it is time to fill in some details about why it was written, how it differs from other […]

8085 Software

This covers creation of software support for the 8085 CPU within the framework of the z88dk and also with MS BASIC 4.7. Specifically, the 8085 undocumented instructions will be covered, and some usage possibilities provided. Future work is to build a re-entrant IEEE floating point library specifically using the stack relative instructions found in the […]

Three Rings for the Z80

Over the past few years I’ve implemented a number of interfaces for Z80 peripherals based on the principal of the interrupt driven ring buffer. Each implementation of a ring exhibits its own peculiarities, based on the specific hardware. But essentially I have but one ring to bring them all and in the darkness bind them. […]

Yet Another Z180 (YAZ180 v2)

Testing on the YAZ180 v1 , shown below, is now complete. I don’t want to use it for further driver and platform development, because the PLCC socket for the 256kB Flash is becoming worn-out. It will continue to operate as an augmented Nascom Basic machine, with an integrated Intel HEX loader (HexLoadr) supporting direct loaded assembler or […]

Yet Another Z180 Project (YAZ180)

I’m thinking about a new project, something a little unusual but still with a rich history of information upon which to base the build. On Tindie, I found the RC2014 project which is a build of a Z80 platform but based on some modern components. That got me thinking. My next project must be a Z80 […]