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FC-handset-spec section 2.4.1: update for PWT melodies and BUZM
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 15 Apr 2022 04:55:26 +0000
parents 8df29c96327a
children 91352355857c
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86:8df29c96327a 87:78d4d362c086
1298 1298
1299 2) For our own FC Libre Dumbphone handset, we will need to implement ringing by 1299 2) For our own FC Libre Dumbphone handset, we will need to implement ringing by
1300 way of the same loudspeaker that will be used for hands-free calls, using the 1300 way of the same loudspeaker that will be used for hands-free calls, using the
1301 Melody E1 feature of Calypso DSP for ringtone melody generation. 1301 Melody E1 feature of Calypso DSP for ringtone melody generation.
1302 1302
1303 2.4.1. Scope limitation on buzzer melodies 1303 2.4.1. Approach to buzzer melodies
1304 1304
1305 Because the option of ringing via Calypso buzzer output is retained only for 1305 My (Mother Mychaela's) original intention was to limit buzzer ringing support
1306 lorekeeping and for minimal-support alien targets, no effort will be expended 1306 to the extremely crude implementation contained in the Condat audio "driver"
1307 toward playing more musical melodies via the buzzer. Our current code (bugfixed 1307 abstraction layer - this demo/prototype/PoC code uses BU mode rather than PWT,
1308 from TI's original) implements just one buzzer ringing sound, consisting of 1308 and it only has one extremely basic ringing sound: alternating 800 Hz and 900 Hz
1309 alternating 800 Hz and 900 Hz tones, using BU mode rather than PWT, and the 1309 tones, no melodies. However, I have subsequently changed my mind on this point:
1310 Mother currently has no plans to implement anything more for the buzzer 1310 upon further reflection, I realized that the audio "driver" in the Condat
1311 configuration. 1311 abstraction layer is a horrendous mess that needs to be cleaned up, and one
1312 very helpful step in cleaning it up will be to remove buzzer functionality from
1313 it. Toward this end, I came up with a new architecture:
1314
1315 * What little remains of the Condat audio "driver" layer (it will be thinned
1316 significantly) will be only for simple audio tones (call waiting, busy,
1317 ringing code for the calling party when the GSM network provides no IBT), and
1318 it won't be involved in ringing, neither in the buzzer config nor in the
1319 Melody E1 loudspeaker config.
1320
1321 * For platforms that feature a magnetic buzzer, there is a new BUZM (buzzer
1322 melody) service implemented in RiViera land (the part of fw architecture
1323 where such application services properly belong), and this BUZM service plays
1324 PWT buzzer melodies, rather than BU mode. The bit-level format for these PWT
1325 melodies is an original FreeCalypso invention, the necessary tool support for
1326 it has been added to the FC host tools package as of fc-host-tools-r17, and
1327 the necessary documentation is maintained in the same place.
1328
1329 For the end user of a FreeCalypso phone that features an old-fashioned buzzer
1330 (e.g., FreeCalypso Lite aftermarket fw on Mot C139), the visible effect of this
1331 architecture change is that a decent selection of varied ringtone melodies can
1332 be implemented. A basic ring that sounds just like TI's original BU version is
1333 still available in PWT mode (it is now composed of alternating G5 and A5 musical
1334 notes, rather than alternating 800 Hz and 900 Hz tones, but it sounds just the
1335 same at least to my ear), but we are now also able to play ringtone melodies of
1336 the same rich kind as those offered by Motorola in their official firmwares for
1337 buzzer-equipped phones.
1312 1338
1313 2.4.2. Melody E1 ringer 1339 2.4.2. Melody E1 ringer
1314 1340
1315 Our Melody E1 ringer implementation will require melody files in FFS, and we 1341 Our Melody E1 ringer implementation will require melody files in FFS, and we
1316 will also have a separate audio mode (in the RiViera Audio Service sense) that 1342 will also have a separate audio mode (in the RiViera Audio Service sense) that