# HG changeset patch # User Mychaela Falconia # Date 1623352085 0 # Node ID 9df8683daec4943e221ae8df3097290b10aa4675 # Parent a415ae467c6d15c1b79ef7c85bd4512be83f24f0 FC-handset-spec: side buttons documented diff -r a415ae467c6d -r 9df8683daec4 FC-handset-spec --- a/FC-handset-spec Thu Jun 10 18:10:35 2021 +0000 +++ b/FC-handset-spec Thu Jun 10 19:08:05 2021 +0000 @@ -406,3 +406,49 @@ not going to use Iota LEDB, and shall only use MAX1916 instead. We also gain a functional improvement over Pirelli DP-L10 by using MAX1916: our keypad backlight intensity will remain the same over the battery discharge range. + +1.6. Side buttons + +In addition to the 21-button main keypad, our FC Libre Dumbphone handset will +include 3 side buttons: two on the left side, intended for volume up/down +control, and one on the right side, serving auxiliary functions. This side +button arrangement is identical to TI's D-Sample and similar to Pirelli DP-L10: +the only difference between our arrangement (matching D-Sample) and Pirelli's +is that Pirelli moved the 3rd side button to the left and designated it as the +camera button. However, we (FreeCalypso) have no interest in ever implementing +any kind of camera on our phones, hence we are moving the 3rd side button back +to where it was in TI's original design (on the right), and we will use it for +purposes of our own invention. + +The starting point UI code we got from TI does not do anything with the right +side button (even though this button exists and works on the D-Sample platform +on which this code was originally developed), hence we have full freedom to +invent our own uses for it. The following uses are envisioned: + +* Long press of this button may be our way of turning the hands-free loudspeaker + on and off, a function that does not exist in the starting point UI code from + TI. + +* When the phone is in its normal idle standby operation (not in a call and not + being poked at by the user, but registered to a GSM network and ready to + accept incoming calls or SMS), the display will be off. Users often desire + to check the time and other status (check coverage, see if they missed any + calls or SMS), which will require pressing any button to turn on the display. + At that point a 30 s timer kicks in, which will turn the display back off + after 30 s of inactivity. However, an argument can be made that keeping the + display on for 30 s if the user only wanted to quickly glance at the time is + a waste of battery. Here is one proposed solution: we can implement a + function where a short press of the right side button when the phone is on its + idle screen will cause the display to turn off immediately and activate the + keyguard. The user can then press the right side button once to turn on the + display and look at it, and then press the same button again to turn it back + off. + +* When we are in a long call, the LCD backlight does not turn off completely, + instead it will go dim - but still readable. Any button presses in this state + are NOT swallowed - they take their regular actions. However, the keypad + backlight turns off fully in this state, and under certain conditions (like + out at night) the user may not be able to see the keypad. If a short press + of the right side button invokes no other action besides switching on full + display brightness and the keypad backlight, this right side button can be + found by touch, and thus solve this particular problem case.