ULA Deconstruction 1
Back in 1996, when there was little hope of finding replacement HCS10017 ULAs for Oric, I began a deconstruction of the ULA's internals, using observed behaviour (the software inputs from memory, hardware outputs). This is the result of that process. There are some known minor discrepancies, so if you think there's a bug or inconsistency, you're probably right.
If you are searching for a replacement ULA for a broken Oric, look on eBay. They are now available from various sellers in Europe as NOS (new-old-stock) parts
Documentation (ZIP file of text and postscript/GIF diagrams) can be downloaded below.
Source, documentation and pictures © 2009-2017 Mike Brown. Visit the website at http://oric.signal11.org.uk for the latest version and contact details.