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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
#include "mbed.h"
#include "Adafruit_SSD1306.h"
#include "counter.h"
#include "spi_init.h"
#define SW_PINS p24, p23, p22, p21
#define SW_PERIOD 20000 // 20ms
#define SINA_SIZE 360
void tout(void);
void square(void);
void triangle(void);
void sine(void);
AnalogOut out_wave(p18);
PinName switch_pin[] = {SW_PINS};
Counter *switch_position[4];
Ticker timer;
Ticker pwm;
volatile uint16_t switch_count[4] = {0, 0, 0, 0};
volatile uint16_t switch_pressed[4] = {0, 0, 0, 0};
volatile uint16_t last_pressed[4] = {0, 0, 0, 0};
uint16_t current_f[4] = {0, 0, 0, 0};
volatile uint16_t update = 0;
volatile uint16_t amp = 0;
const double pi = 3.141592653589793238462;
const double offset = 65535 / 2; // Offset is 1/2 the total bits
double rads = 0.0;
uint16_t sample = 0;
uint16_t sineArray[SINA_SIZE];
int wave_type = -1;
int triangleDirection = 1;
// Initialise display
SPInit gSpi(D_MOSI_PIN, NC, D_CLK_PIN);
Adafruit_SSD1306_Spi oled(gSpi, D_DC_PIN, D_RST_PIN, D_CS_PIN, 64, 128);
int main(void)
{
for (int i = 0; i < SINA_SIZE; i++) {
rads = (pi * i) / (SINA_SIZE / 2.0f);
sineArray[i] = (uint16_t)(0.5f * (offset * (cos(rads + pi))) + offset);
}
uint16_t frequency = 0;
uint16_t old_frequency = 0;
out_wave.write(0.5);
oled.setRotation(2);
wait(0.5);
// Enable ISR for the switch rising edge
for (int i = 0; i < 4; ++i) {
switch_position[i] = new Counter(switch_pin[i]);
}
// Attach switch sampling timer ISR to the timer instance with the
// required period
timer.attach_us(&tout, SW_PERIOD);
oled.clearDisplay();
for (;;) {
if (update) {
update = 0;
oled.setTextCursor(0, 0);
oled.printf("Wave type: %d \n", wave_type);
oled.printf("Sq:2 Tr:1 Sin:0");
// Write the latest switch osciallor count
for (int i = 3; i >= 0; --i) {
if (wave_type < 0){
if (switch_pressed[i] && !last_pressed[i]){
wave_type = i;
oled.setTextCursor(0, 0);
}
} else {
current_f[i] += (switch_pressed[i] && !last_pressed[i]);
if (current_f[i] > 9)
current_f[i] = 0;
oled.printf("\nS:%u C:%05u N:%u", switch_pressed[i], switch_count[i], current_f[i]);
}
}
old_frequency = frequency;
frequency = 1000 * current_f[3] + 100 * current_f[2] + 10 * current_f[1] + current_f[0];
if (frequency != old_frequency) {
oled.printf("\nF:%u ", frequency);
if (frequency){
switch(wave_type){
case 1:
pwm.attach_us( &triangle, 1000000 / (frequency * SINA_SIZE));
break;
case 0:
pwm.attach_us( &sine, 1000000 / (frequency * 100));
break;
default:
pwm.attach_us( &square, 1000000 / (frequency * 2));
}
}
}
// Copy the display buffer to the display
oled.display();
}
}
}
// Interrupt Service Routine for the switch sampling timer
void tout(void)
{
// Query how many times switch triggered
for (int i = 0; i < 4; ++i) {
switch_count[i] = switch_position[i]->read();
switch_position[i]->write(0);
last_pressed[i] = switch_pressed[i];
if (switch_count[i] < 600)
switch_pressed[i] = 1;
else if (switch_count[i] > 700)
switch_pressed[i] = 0;
}
// Update display
update = 1;
}
void square(void){
out_wave = !out_wave;
}
void triangle(void)
{
amp += triangleDirection;
out_wave = (float)amp / 100;
if (amp == 100 || amp == 0)
triangleDirection = triangleDirection*-1;
}
void sine(void)
{
if (amp == SINA_SIZE)
amp = 0;
out_wave.write_u16(sineArray[amp]);
amp++;
}
|
