# HG changeset patch # User Mychaela Falconia # Date 1623376042 0 # Node ID cb8d43a5023c12f9ae396f49dc963436aec62e99 # Parent f0419ac0a8155520aeaa33922ccd1da39e6524e2 FC-handset-spec: vibrator documented diff -r f0419ac0a815 -r cb8d43a5023c FC-handset-spec --- a/FC-handset-spec Fri Jun 11 00:13:39 2021 +0000 +++ b/FC-handset-spec Fri Jun 11 01:47:22 2021 +0000 @@ -640,3 +640,43 @@ source, and software complexity is minimal: the melody playing engine has already been implemented by TI, we only need to call RiViera Audio Service API functions. + +1.9. Vibrator + +All traditional cellphones include a vibrator, and ours needs to include one +too. Our firmware will need to offer the options of being silent, vibrating +only, ringing only, or ringing and vibrating on an incoming call or SMS - all +of these options are genuinely useful to a heavy-duty phone user in different +situations. + +In terms of functionality, the vibrator is envisioned as a simple on/off control +in the hardware, with higher-level "pulse train" functionality implemented in +the firmware. As far as end user experience goes, the Mother's plan is to copy +the way the vibrator works on the Pirelli DP-L10. On this to-be-replaced or +to-be-recreated reference phone, the vibrator works as follows: when an incoming +call arrives in vibrating alert mode, the firmware turns the vibrator on for +500 ms, then turns it off for 500 ms, and the cycle endlessly repeats until the +call is either answered or dropped. This 500 ms on/off cycling is purely a +firmware function, the hardware control is an on/off switch. + +Looking at the hardware implementation of the vibrator driving circuit in the +Motorola C1xx family and in the Pirelli DP-L10, both designs support a form of +"analog" control of the vibrator beyond simple on/off. In the Mot C1xx family +the vibrator is controlled by the output of Iota auxiliary DAC, whereas in the +Pirelli DP-L10 Calypso BU output has been repurposed to control the vibrator, +allowing either full-on or PWM driving. However, Pirelli's firmware appears to +never operate the vibrator in any way other than fully on, and there is no +evidence of Mot C1xx firmwares applying any analog control to their vibrator +either. + +The Mother's tentative plan for our FC Libre Dumbphone handset is to copy +Pirelli's approach in both hardware and firmware: repurpose Calypso BU output +for vibrator control (we won't have a buzzer, see section 1.8), allowing the +possibility of PWM, but have our firmware only use fully-on and fully-off +states, at least initially. However, because we won't have a vibrator on our +Venus development board, only in the final handset, this decision does not have +to be made right now. + +Because our firmware will be designed for a simple on/off vibrator control, +during fw development on the Venus board it will be trivial to use a LED to +simulate the vibrator on/off state.