1 * Pattern format for LED pattern trigger 1 * Pattern format for LED pattern trigger
2 2
3 The pattern is given by a series of tuples, of 3 The pattern is given by a series of tuples, of brightness and duration (ms).
4 The LED is expected to traverse the series and 4 The LED is expected to traverse the series and each brightness value for the
5 specified duration. Duration of 0 means bright 5 specified duration. Duration of 0 means brightness should immediately change to
6 new value, and writing malformed pattern deact 6 new value, and writing malformed pattern deactivates any active one.
7 7
8 1. For gradual dimming, the dimming interval n 8 1. For gradual dimming, the dimming interval now is set as 50 milliseconds. So
9 the tuple with duration less than dimming inte 9 the tuple with duration less than dimming interval (50ms) is treated as a step
10 change of brightness, i.e. the subsequent brig 10 change of brightness, i.e. the subsequent brightness will be applied without
11 adding intervening dimming intervals. 11 adding intervening dimming intervals.
12 12
13 The gradual dimming format of the software pat 13 The gradual dimming format of the software pattern values should be:
14 "brightness_1 duration_1 brightness_2 duration 14 "brightness_1 duration_1 brightness_2 duration_2 brightness_3 duration_3 ...".
15 For example (using sysfs interface): 15 For example (using sysfs interface):
16 16
17 echo 0 1000 255 2000 > pattern 17 echo 0 1000 255 2000 > pattern
18 18
19 It will make the LED go gradually from zero-in 19 It will make the LED go gradually from zero-intensity to max (255) intensity in
20 1000 milliseconds, then back to zero intensity 20 1000 milliseconds, then back to zero intensity in 2000 milliseconds:
21 21
22 LED brightness 22 LED brightness
23 ^ 23 ^
24 255-| / \ / \ / 24 255-| / \ / \ /
25 | / \ / \ / 25 | / \ / \ /
26 | / \ / \ / 26 | / \ / \ /
27 | / \ / \ / 27 | / \ / \ /
28 0-| / \/ \/ 28 0-| / \/ \/
29 +---0----1----2----3----4----5----6------- 29 +---0----1----2----3----4----5----6------------> time (s)
30 30
31 2. To make the LED go instantly from one brigh 31 2. To make the LED go instantly from one brightness value to another, we should
32 use zero-time lengths (the brightness must be 32 use zero-time lengths (the brightness must be same as the previous tuple's). So
33 the format should be: "brightness_1 duration_1 33 the format should be: "brightness_1 duration_1 brightness_1 0 brightness_2
34 duration_2 brightness_2 0 ...". 34 duration_2 brightness_2 0 ...".
35 For example (using sysfs interface): 35 For example (using sysfs interface):
36 36
37 echo 0 1000 0 0 255 2000 255 0 > pattern 37 echo 0 1000 0 0 255 2000 255 0 > pattern
38 38
39 It will make the LED stay off for one second, 39 It will make the LED stay off for one second, then stay at max brightness for
40 two seconds: 40 two seconds:
41 41
42 LED brightness 42 LED brightness
43 ^ 43 ^
44 255-| +---------+ +---------+ 44 255-| +---------+ +---------+
45 | | | | | 45 | | | | |
46 | | | | | 46 | | | | |
47 | | | | | 47 | | | | |
48 0-| -----+ +----+ +---- 48 0-| -----+ +----+ +----
49 +---0----1----2----3----4----5----6------- 49 +---0----1----2----3----4----5----6------------> time (s)
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