*12-bit colour palette
*Hardware 16 hardware sprites
*Vertical and horizontal per-pixel hardware soft scrolling (in complement with register 12&13 of the CRTC)
*Screen splitting
*Programmable raster interrupts
*Vectored interrupts
*3 DMA sound channels
*Specific ROM switching
*8-bit printer port (with bit3 of CRTC register 12)
Sprites will be displayed at coordinates based on the internal counters of the CRTC. Sprite X coordinate is based on HCC. Sprite Y coordinate is based on VCC and VLC.
When the data for a sprite is read or written, that sprite is removed from the display for the duration of the access. Thus sprite data should only be accessed during retraced time or while the raster is scanning somewhere else, otherwise there is a risk of disruption of the display. [[Original Arnold V Specs|Source]]
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POR column indicates whether a register has power-on reset. A "N" indicates that the contents of a register are undefined at power-on.
Writes to unused areas of the ASIC I/O page are not persisted. [https://www.cpcwiki.eu/forum/games/harrier-attack-reloaded/msg247703/#msg247703 Source]
Beware, when booting your software from cartridge. The Z80 is in Interrupt Mode 0 by default. The Stack Pointer is uninitialized. FDC is in DMA mode by default. And the hardware sprites memory has random value.
Anyway, you have to initialize all internal components (Z80, PPI, CRTC, AY, etc) when you are booting from cartridge.
==Related pages==
*[[Arnold V specs]]*[[Original Arnold V Specs Revised]]
*[[Extra CPC Plus Hardware Information]]
*[https://www.cpcwiki.eu/index.php/Amstrad_Cartridge_Identification_Device ACID] Protection chip used in the cartridges of the Plus series and the GX4000 game console
*[[Programming:Unlocking ASIC]]
*[[B-ASIC]]