FreeCalypso > hg > freecalypso-docs
diff FC-handset-spec @ 87:78d4d362c086
FC-handset-spec section 2.4.1: update for PWT melodies and BUZM
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 15 Apr 2022 04:55:26 +0000 |
parents | 8df29c96327a |
children | 91352355857c |
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--- a/FC-handset-spec Fri Apr 15 01:40:32 2022 +0000 +++ b/FC-handset-spec Fri Apr 15 04:55:26 2022 +0000 @@ -1300,15 +1300,41 @@ way of the same loudspeaker that will be used for hands-free calls, using the Melody E1 feature of Calypso DSP for ringtone melody generation. -2.4.1. Scope limitation on buzzer melodies +2.4.1. Approach to buzzer melodies + +My (Mother Mychaela's) original intention was to limit buzzer ringing support +to the extremely crude implementation contained in the Condat audio "driver" +abstraction layer - this demo/prototype/PoC code uses BU mode rather than PWT, +and it only has one extremely basic ringing sound: alternating 800 Hz and 900 Hz +tones, no melodies. However, I have subsequently changed my mind on this point: +upon further reflection, I realized that the audio "driver" in the Condat +abstraction layer is a horrendous mess that needs to be cleaned up, and one +very helpful step in cleaning it up will be to remove buzzer functionality from +it. Toward this end, I came up with a new architecture: + +* What little remains of the Condat audio "driver" layer (it will be thinned + significantly) will be only for simple audio tones (call waiting, busy, + ringing code for the calling party when the GSM network provides no IBT), and + it won't be involved in ringing, neither in the buzzer config nor in the + Melody E1 loudspeaker config. -Because the option of ringing via Calypso buzzer output is retained only for -lorekeeping and for minimal-support alien targets, no effort will be expended -toward playing more musical melodies via the buzzer. Our current code (bugfixed -from TI's original) implements just one buzzer ringing sound, consisting of -alternating 800 Hz and 900 Hz tones, using BU mode rather than PWT, and the -Mother currently has no plans to implement anything more for the buzzer -configuration. +* For platforms that feature a magnetic buzzer, there is a new BUZM (buzzer + melody) service implemented in RiViera land (the part of fw architecture + where such application services properly belong), and this BUZM service plays + PWT buzzer melodies, rather than BU mode. The bit-level format for these PWT + melodies is an original FreeCalypso invention, the necessary tool support for + it has been added to the FC host tools package as of fc-host-tools-r17, and + the necessary documentation is maintained in the same place. + +For the end user of a FreeCalypso phone that features an old-fashioned buzzer +(e.g., FreeCalypso Lite aftermarket fw on Mot C139), the visible effect of this +architecture change is that a decent selection of varied ringtone melodies can +be implemented. A basic ring that sounds just like TI's original BU version is +still available in PWT mode (it is now composed of alternating G5 and A5 musical +notes, rather than alternating 800 Hz and 900 Hz tones, but it sounds just the +same at least to my ear), but we are now also able to play ringtone melodies of +the same rich kind as those offered by Motorola in their official firmwares for +buzzer-equipped phones. 2.4.2. Melody E1 ringer