forked from hybridgroup/gobot
-
Notifications
You must be signed in to change notification settings - Fork 0
/
pwm_pin.go
81 lines (69 loc) · 1.64 KB
/
pwm_pin.go
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
package beaglebone
import (
"fmt"
"github.com/hybridgroup/gobot/sysfs"
"os"
"strings"
)
type pwmPin struct {
pinNum string
pwmDevice string
}
// newPwmPin creates a new pwm pin with specified pin number
func newPwmPin(pinNum string, ocp string) *pwmPin {
var fi sysfs.File
d := &pwmPin{
pinNum: strings.ToUpper(pinNum),
}
pwmDevice, err := glob(fmt.Sprintf("%v/pwm_test_%v.*", ocp, d.pinNum))
if err != nil {
panic(err)
}
d.pwmDevice = pwmDevice[0]
for i := 0; i < 10; i++ {
fi, err = sysfs.OpenFile(fmt.Sprintf("%v/run", d.pwmDevice), os.O_RDWR|os.O_APPEND, 0666)
defer fi.Close()
if err != nil && i == 9 {
panic(err)
} else {
break
}
}
fi.WriteString("1")
fi.Sync()
for {
if _, err := sysfs.OpenFile(fmt.Sprintf("%v/period", d.pwmDevice), os.O_RDONLY, 0644); err == nil {
break
}
}
for {
if _, err := sysfs.OpenFile(fmt.Sprintf("%v/duty", d.pwmDevice), os.O_RDONLY, 0644); err == nil {
break
}
}
return d
}
// pwmWrite writes to a pwm pin with specified period and duty
func (p *pwmPin) pwmWrite(period string, duty string) {
f1, err := sysfs.OpenFile(fmt.Sprintf("%v/period", p.pwmDevice), os.O_WRONLY|os.O_APPEND, 0666)
defer f1.Close()
if err != nil {
panic(err)
}
f1.WriteString(period)
f2, err := sysfs.OpenFile(fmt.Sprintf("%v/duty", p.pwmDevice), os.O_WRONLY|os.O_APPEND, 0666)
defer f2.Close()
if err != nil {
panic(err)
}
f2.WriteString(duty)
}
// releae writes string to close a pwm pin
func (p *pwmPin) release() {
fi, err := sysfs.OpenFile(fmt.Sprintf("%v/run", p.pwmDevice), os.O_WRONLY|os.O_APPEND, 0666)
defer fi.Close()
if err != nil {
panic(err)
}
fi.WriteString("0")
}