Changes
* CRTC hardware CURSOR interrupt support.
* The LIGHT PEN/GUN connector.
==Technical description==
- 6 audio channels sound with programmable frequency. (stereo line out and speaker mono mix in)
- 4 counter/timer channels for programmable interrupt. (including NMI)
- IM2 vectorized interrupt support
- Raster lines interrupt support
- CRTC hardware CURSOR
The board main feature is the Zilog Z80 Counter Timer Circuit, the best friend of the Zilog Z80 CPU.
The CTC is linked to the CPU to allow it to manage vectorized interrupt (IM2) and handling triggered events.
Programmers can only get benefit of that to save CPU time and make complex programs more easy to achieve.
I can only invite them to read the Zilog CTC data-sheet for more informations. (it's really easy to use)
Because the CPC expansion port have some interesting signals on it, it had been a shame to not use them.
- CTC channel 0 is a programable audio clock generator. i.e. allow to replay ST or ZX sound on a CPC using AUDIO pin.
- CTC channel 1 is linked to the CURSOR pin and triggered by the NMI pin. Allow accurate hi priority rasters effects.
- CTC channel 2 and 3 are linked together and offers 2x8bit or 1x16bit user purpose timer or counter.
ADDER is the ADDress decodER part of the board. It manage all the ICs.
Because ports are direct access to the hardware, it's really fast.
- CTC channels: #F880, 81, 82, 83
- Audio right: #F884, #F984
- Audio left: #F888, #F988
- Soft reset: #F8FF
At end, the LIGHTPEN pin is rooted to a 4 pins connector for plugging compatible hardware through an adapter.
==Hardware Installation==
