FreeCalypso > hg > freecalypso-tools
comparison doc/RVTMUX @ 223:ac49d8814893
doc/RVTMUX: keepalive mechanism documented
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 20 May 2017 22:05:46 +0000 |
| parents | d9307880f59f |
| children | 05dc91d011a6 |
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| 222:7168f63fc3b8 | 223:ac49d8814893 |
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| 233 whereas packets flowing the other way carry ATI's responses to commands and | 233 whereas packets flowing the other way carry ATI's responses to commands and |
| 234 asynchronous notifications such as incoming calls. | 234 asynchronous notifications such as incoming calls. |
| 235 | 235 |
| 236 The host utility for talking AT commands to a FreeCalypso GSM device via RVTMUX | 236 The host utility for talking AT commands to a FreeCalypso GSM device via RVTMUX |
| 237 is fc-shell; it works via rvinterf just like fc-fsio and fc-tmsh. | 237 is fc-shell; it works via rvinterf just like fc-fsio and fc-tmsh. |
| 238 | |
| 239 Keepalive mechanism | |
| 240 =================== | |
| 241 | |
| 242 Another FreeCalypso addition to TI's RVTMUX interface is our optional keepalive | |
| 243 mechanism. The FreeCalypso family includes many subprojects, and one of these | |
| 244 subprojects involves running modem-like firmware (control via AT commands only, | |
| 245 no local UI) on Mot C1xx phones. Having a device that was originally made to | |
| 246 be a phone with LCD and buttons turn into a serially-controlled pseudo-modem | |
| 247 (LCD stays dark, buttons do nothing) feels quite weird, and this situation is | |
| 248 exacerbated on low-end Mot C1xx models that have small RAM and thus require our | |
| 249 pseudo-modem fw to be flashed. | |
| 250 | |
| 251 Our optional keepalive mechanism is intended for the latter scenario. There | |
| 252 will be an optional feature added to pseudo-modem fw builds for C1xx targets | |
| 253 (not yet implemented as of this writing) to have the firmware send periodic | |
| 254 keepalive queries out the serial port, to see if there is a running rvinterf | |
| 255 process on the other end of the wire, and automatically power off if there is | |
| 256 no keepalive response. | |
| 257 | |
| 258 Code has been added to rvinterf to respond with a keepalive answer packet when | |
| 259 a keepalive query packet is received; the feature has been implemented on the | |
| 260 rvinterf side ahead of the target fw so that when and if we do get around to | |
| 261 implementing the target side, the necessary rvinterf support will be there | |
| 262 waiting for us. |