Below are some versions of the original CPC+ specs. There is also an edited version in cpcwiki: Arnold V Specs Revised.
"Arnold V" Specification - Issue 1.4 - March 1990
Specs coming from Kevin Thacker's webpage, http://www.cpctech.org.uk/.
- txt version or zipped html version - includes info on IVR register
"Arnold V" Specification - Issue 1.5 - 10th April 1990
Slightly newer version, coming from Kevin Thacker's webpage, http://www.cpctech.org.uk/, too. There are several differences to issue 1.4, some notably are: Issue 1.5 includes detailed info on the ASIC Unlocking Sequence. However, info on the Interrupt Vector Register (IVR) at address 6805h is removed in Issue 1.5.
- txt version or zipped html version - includes details on ASIC Unlocking
"Arnold V" Specification - RTF version
The RTF file has been the first CPC+ document that showed up in the internet, coming from Cliff Lawsons webpage, http://web.ukonline.co.uk/cliff.lawson/. The file doesn't have a version number, but it seems to resemble Issue 1.5. The formatting is slightly distorted, for example, there are missing line breaks in the printer pin-out table.
- rtf version - rtf (rich text format) is a html-style file format, supported by Microsoft Wordpad, which is a text editing program included with Microsoft Windows 9X.