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
|
#include "mbed.h"
#include "spi_init.h"
#include "counter.h"
#include "Adafruit_SSD1306.h"
#define SW_PINS p22, p23, p24, p25
#define SW_PERIOD 20000 // 20ms
void tout(void);
// Onboard LED
DigitalOut alive(LED1);
PinName switch_pin[] = { SW_PINS };
Counter *switch_position[4];
Ticker timer;
volatile uint16_t switch_count[4] = { 0, 0, 0, 0 };
volatile uint16_t switch_pressed[4] = { 0, 0, 0, 0 };
volatile uint16_t update = 0;
uint16_t max_count[4];
// 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)
{
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();
oled.printf("%ux%u Group Ay08-04\r\n", oled.width(), oled.height());
for (;;) {
if (update) {
update = 0;
oled.setTextCursor(0, 0);
//Write the latest switch osciallor count
for (int i = 0; i < 4; ++i) {
oled.printf("\nS:%u C:%05u", switch_pressed[i], switch_count[i]);
}
//Copy the display buffer to the display
oled.display();
alive = !alive;
}
}
}
//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);
if (max_count[i] < switch_count[i])
max_count[i] = switch_count[i];
if (switch_count[i] < (3*max_count[i])/5)
switch_pressed[i] = 1;
else if (switch_count[i] > (4*max_count[i])/5)
switch_pressed[i] = 0;
}
// Update display
update = 1;
}
|
