| * Pattern format for LED pattern trigger |
| |
| The pattern is given by a series of tuples, of brightness and duration (ms). |
| The LED is expected to traverse the series and each brightness value for the |
| specified duration. Duration of 0 means brightness should immediately change to |
| new value, and writing malformed pattern deactivates any active one. |
| |
| 1. For gradual dimming, the dimming interval now is set as 50 milliseconds. So |
| the tuple with duration less than dimming interval (50ms) is treated as a step |
| change of brightness, i.e. the subsequent brightness will be applied without |
| adding intervening dimming intervals. |
| |
| The gradual dimming format of the software pattern values should be: |
| "brightness_1 duration_1 brightness_2 duration_2 brightness_3 duration_3 ...". |
| For example (using sysfs interface): |
| |
| echo 0 1000 255 2000 > pattern |
| |
| It will make the LED go gradually from zero-intensity to max (255) intensity in |
| 1000 milliseconds, then back to zero intensity in 2000 milliseconds: |
| |
| LED brightness |
| ^ |
| 255-| / \ / \ / |
| | / \ / \ / |
| | / \ / \ / |
| | / \ / \ / |
| 0-| / \/ \/ |
| +---0----1----2----3----4----5----6------------> time (s) |
| |
| 2. To make the LED go instantly from one brightness value to another, we should |
| use zero-time lengths (the brightness must be same as the previous tuple's). So |
| the format should be: "brightness_1 duration_1 brightness_1 0 brightness_2 |
| duration_2 brightness_2 0 ...". |
| For example (using sysfs interface): |
| |
| echo 0 1000 0 0 255 2000 255 0 > pattern |
| |
| It will make the LED stay off for one second, then stay at max brightness for |
| two seconds: |
| |
| LED brightness |
| ^ |
| 255-| +---------+ +---------+ |
| | | | | | |
| | | | | | |
| | | | | | |
| 0-| -----+ +----+ +---- |
| +---0----1----2----3----4----5----6------------> time (s) |
