blob: 2059c9be9e79eca1fb15afd36af7415dfa16f78a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>
#include <util/delay.h>
#include <stdlib.h>
#include "display.h"
#include "font.h"
Display display;
Display::Display()
{
char_pos = -1;
update_delay = 400;
}
void Display::disable()
{
TIMSK0 &= ~_BV(TOIE0);
PORTB = 0;
PORTD = 0;
}
void Display::enable()
{
// Ports B and D drive the dot matrix display -> set all as output
DDRB = 0xff;
DDRD = 0xff;
// Enable 8bit counter with prescaler=8 (-> timer frequency = 1MHz)
TCCR0A = _BV(CS01);
// raise timer interrupt on counter overflow (-> interrupt frequency = ~4kHz)
TIMSK0 = _BV(TOIE0);
}
void Display::multiplex()
{
static uint16_t scroll;
/*
* To avoid flickering, do not put any code (or expensive index
* calculations) between the following three lines.
*/
PORTB = 0;
PORTD = disp_buf[active_col];
PORTB = _BV(active_col);
if (++active_col == 8)
active_col = 0;
if (++scroll == update_delay) {
scroll = 0;
need_update = 1;
}
}
void Display::update() {
uint8_t i, glyph_len;
uint8_t *glyph_addr;
if (need_update) {
need_update = 0;
for (i = 0; i < 7; i++) {
disp_buf[i] = disp_buf[i+1];
}
glyph_addr = (uint8_t *)pgm_read_ptr(&font[(uint8_t)display.string[str_pos]]);
glyph_len = pgm_read_byte(&glyph_addr[0]);
char_pos++;
if (char_pos > glyph_len) {
char_pos = 0;
str_pos++;
}
if (display.string[str_pos] == 0) {
str_pos = 0;
}
if (char_pos == 0) {
disp_buf[7] = 0xff; // whitespace
} else {
disp_buf[7] = ~pgm_read_byte(&glyph_addr[char_pos]);
}
}
}
void Display::reset()
{
for (uint8_t i = 0; i < 8; i++)
disp_buf[i] = 0xff;
str_pos = 0;
char_pos = -1;
}
void Display::setString(const char *new_str)
{
setString((char *)new_str);
}
void Display::setString(char *new_str)
{
reset();
for (uint8_t i = 0; new_str[i] != 0; i++) {
string[i] = new_str[i];
}
}
/*
* Draws a single display column. This function should be called at least once
* per millisecond.
*
* Current configuration:
* Called every 256 microseconds. The whole display is refreshed every 2048us,
* giving a refresh rate of ~500Hz
*/
ISR(TIMER0_OVF_vect)
{
display.multiplex();
}
|
