The final cost down models came just before the release of the Amstrad plus.
The same chip was used within the CPC464 and CPC6128.
In CRTC terms it operates almost the same as the CRTC within the Plus ASIC. The following information relating to the pins of the IC was tested and verified by Gerald:
==L4N6 pin==
- ROMDIS act as the DDI ROMDIS as it is active even during ram access
10943-0
==/EXP== When the DDI1 extension is not plugged, /EXP is pulled high, and /ROM2 signal is in fact ROM0 and replace the BASIC. As no ROM is connected, it just crash !
==Bonus==
- on the following page, Gate Array and ASIC Pin-Outs - CPCWiki, pin 35 and 36 are undocumented.