The '''CRTC''' (Cathode Ray Tube Controller) helps to generate the video signal of the Amstrad CPC.
NOTE: This document describes the functionality in terms of the CPC with it's its separate CRTC and Gate-Array. The Plus has both integrated into the same IC, but could be considered to have 2 two functional blocks, one for CRTC and one for Gate-Array. In this document the term 'Gate-Array ' is used, but this also applies to the ASIC.
== Overview ==
R31 is described in the UM6845R documentation as "Dummy Register".
It's Its use is described in the documentation for the Rockwell R6545 in combination with R18, R19 and R8 and the Status Register.
In the UM6845R it appears to have no effect. Reading and writing does nothing. Reading it returns 0x0ff.