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/*
* Copyright (C) 2016 by Daniel Friesel
*
* License: You may use, redistribute and/or modify this file under the terms
* of either:
* * The GNU LGPL v3 (see COPYING and COPYING.LESSER), or
* * The 3-clause BSD License (see COPYING.BSD)
*
*/
#include <avr/io.h>
#include <stdlib.h>
/**
* Describes the type of an animation object. The Storage class reserves four
* bits for the animation type, so up to 16 types are supported.
*/
enum class AnimationType : uint8_t {
TEXT = 1,
FRAMES = 2
};
/**
* Generic struct for anything which can be displayed, e.g. texts or
* sequences of frames.
*/
struct animation {
/**
* Specific kind of animation described in this struct. Controls the
* behaviour of Display::multiplex() and Display::update().
*/
AnimationType type;
/**
* Length of data in bytes
*/
uint16_t length;
/**
* * If type == AnimationType::TEXT: Text scroll speed in columns per TODO
* * If type == AnimationType::FRAMES: Frames per TODO
*/
uint8_t speed;
/**
* Delay after the last text symbol / animation frame. Not yet supported.
*/
uint8_t delay;
/**
* Scroll mode / direction. Not yet supported.
*/
uint8_t direction;
/**
* * If type == AnimationType::TEXT: character array pointing to the
* animation text in standard ASCII format (+ special font chars)
* * If type == AnimationType::FRAMES: Frame array. Each element encodes
* a display column (starting with the leftmost one), each group of
* eight elements is a frame.
*/
uint8_t *data;
};
typedef struct animation animation_t;
/**
* Controls the display. Handles multiplexing, scrolling and supports loading
* arbitrary animations.
*/
class Display {
private:
animation_t *current_anim;
uint8_t need_update;
uint8_t active_col;
uint8_t disp_buf[8];
uint8_t str_pos;
uint8_t str_chunk;
int8_t char_pos;
enum AnimationStatus : uint8_t {
RUNNING,
SCROLL_BACK,
PAUSED
};
AnimationStatus status;
public:
Display();
/**
* Enable the display driver.
* Configures ports B and D as output and enables the display
* timer and interrupt.
*/
void enable(void);
/**
* Disable the display driver.
* Turns off both the display itself and the display timer.
*/
void disable(void);
/**
* Draws a single display column. Called every 256 microseconds
* by the timer interrupt (TIMER0_OVF_vect), resulting in
* a display refresh rate of ~500Hz (one refresh per 2048µs)
*/
void multiplex(void);
/**
* Reset display and animation state. Fills the screen with "black"
* (that is, no active pixels) and sets the animation offset to zero.
*/
void reset(void);
/**
* Update display content.
* Checks current_anim->speed and current_anim->type and scrolls
* the text / advances a frame when appropriate. Does nothing
* otherwise.
*/
void update(void);
/**
* Set the active animation to be shown on the display. Automatically
* calls reset().
*
* @param anim active animation. Note that the data is not copied,
* so anim has to be kept in memory until a new one is loaded
*/
void show(animation_t *anim);
};
extern Display display;
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