* not even tasks like colour generation are abstracted — the programmer is given a 1bpp pixel output that is in-phase with the NTSC video signal and is expected to generate colours through proper placement of dots; and
* there are zero interrupt sources in an unexpanded machine. There is no way to keep track of time other than processor cycle counting.
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==Input==
The keyboard that cannot communicate multiple simultaneous keypresses, which makes playing games by keyboard difficult.
However, it is equipped with analogue and trigger inputs, which are most commonly used for two two-axis analogue joysticks with two buttons, accepted by the majority of games.
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