Characterising Am9511A-1 APU

I’ve built a Z180 based board, supporting the AM9511A APU. Partly for historical enjoyment. Partly because the AM9511A-1 is actually still faster at arithmetic than “modern” Z80 devices. For example, from the Am9511/Am9512 Floating Point Processor Manual by Steven Cheng, we have comparison tables. On average the Am9511A APU (at 1.966MHz) produces a hardware floating […]

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 […]