Windows; Cursor; Polyphonic Sound; Printer Port - AMSTRAD CPC464 User Manual

The number of available INKS depends on the screen modes selected. Each INK can be set to a pair
of colours ie flashing; or a single colour ie steady. The number of usable inks at any time depends on
,
the screen mode as previously defined. The text PAPER, text PEN and graphics P E N can then be
set to an available ink.
The text writing,can be set to be translucent or opaque: ie it will either ignore the paper colour and
overwrite the graphics, or completely overwrite the background.

Windows

The user can select up to eight text windows into which characters are written, and also a graphics
window into which plotting may be performed.
Windows are reset to defaults when the screen mode is set.
NB: If the text window is equivalent to the entire screen (default), then rapid rolling is achieved by
hardware. If the text window is less than the available screen, then rolling is achieved by software,
which is correspondingly slower.

Cursor

The cursor is disabled during periods when the CPU is not requiring keyboard input, thus acting as
an automatic prompt. The cursor is represented by an inverse square of colour.

Polyphonic Sound

The sound facilities of the CPC464 are generated using the industry standard sound generator
device from General Instrument' s AY8910 family. The device operates with 3 channels (voices), each
of which can be independently set for tone and amplitude. White noise may be added as required.
The three channels appear as left, right and centre (using the stereo extension jack). The internal
loudspeaker produces a mixed monaural output.
The software provides envelope control facilities for amplitude and tone. The sound generator
device' s internal amplitude enveloping is normally not used.

Printer Port

An industry standard Centronics compatible parallel printer port is provided, using the ' Busy' signal
line for performing handshake operations.
Expansion Support
Many hardware interfaces are available via jump blocks or indirection to provide software expansion
facilities. AMSTRAD will be introducing, amongst other items, disc drives, serial interfaces with
driver software in ROM etc.
Coordinates
The text origin is the top left hand corner of the screen, and physical positions on the screen change
with the screen mode.
The graphics origin is the bottom left hand corner, and assumes the screen is in High Resolution
mode at all times -although calculations for inks will be performed correctly in all screen modes.
NB
In normal screen mode, each pixel has TWO horizontal addresses, and either may be used. In
multicolour mode, each pixel has FOUR horizontal addresses, and any of the four can be used to
define the pixel position.