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comparison FCDEV3B-repackaging @ 6:700d6cff63bb
FCDEV3B-repackaging: new ideas regarding quadband RFFE TSPACT wiring
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 11 Oct 2018 05:44:22 +0000 |
| parents | f920c9a68d45 |
| children | f57f29dcc6d6 |
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| 5:f920c9a68d45 | 6:700d6cff63bb |
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| 249 hence anyone seeking this approach would need to be prepared to pay for that | 249 hence anyone seeking this approach would need to be prepared to pay for that |
| 250 step. | 250 step. |
| 251 | 251 |
| 252 If anyone ever does pay for the creation of a quadband version of our | 252 If anyone ever does pay for the creation of a quadband version of our |
| 253 FreeCalypso modem solution, be it in BenQ's physical form factor or some other, | 253 FreeCalypso modem solution, be it in BenQ's physical form factor or some other, |
| 254 this quadband modem will need a different firmware build configuration: there | 254 what about the firmware? For a long time I thought that a quadband modem would |
| 255 is no way to have the same fw image work on both triband and quadband modems | 255 need a different firmware build configuration because of incompatible TSPACT |
| 256 given that the RFFE control signals are different, and there would be no way for | 256 signals. Our current triband modem (copied from Openmoko) has them wired like |
| 257 the fw to autodetect which hw it is running on. But all of the other design | 257 this: |
| 258 guidelines listed above should still be followed, so we can have only two fw | 258 |
| 259 build configurations (triband and quadband) without an explosion of further | 259 TSPACT2 = Tx high bands |
| 260 build variants for different GPIO wiring and whatnot. | 260 TSPACT1 = Rx PCS band |
| 261 TSPACT4 = Tx low bands | |
| 262 | |
| 263 But TI's original TSPACT wiring for the quadband RFFE on their Leonardo and | |
| 264 E-Sample boards was different: | |
| 265 | |
| 266 TSPACT2 = Tx low bands | |
| 267 TSPACT1 = Tx high bands | |
| 268 TSPACT4 = Rx GSM850 band | |
| 269 | |
| 270 These two TSPACT signal assignments are mutually incompatible, hence if we make | |
| 271 a quadband modem following TI's original Leonardo/E-Sample TSPACT wiring, it | |
| 272 won't be able to share the same fw with our triband modems. But then I got an | |
| 273 idea: what if we wire them up in our own creative way as follows: | |
| 274 | |
| 275 TSPACT2 = Tx high bands | |
| 276 TSPACT4 = Tx low bands | |
| 277 TSPACT5 = Rx GSM850 band | |
| 278 | |
| 279 Then we can have the same fw build configuration support both triband and | |
| 280 quadband FreeCalypso modems by driving the signals as follows: | |
| 281 | |
| 282 TSPACT1 = Rx PCS band | |
| 283 TSPACT2 = Tx high bands | |
| 284 TSPACT4 = Tx low bands | |
| 285 TSPACT5 = Rx GSM850 band | |
| 286 | |
| 287 TSPACT1 will be driven but unused on quadband modems, whereas TSPACT5 will be | |
| 288 driven but unused on triband ones like our current FCDEV3B. To me (Mother | |
| 289 Mychaela) being able to have the same fw among *all* FreeCalypso modem variants, | |
| 290 both triband and quadband, is more valuable than the symbolic act of recreating | |
| 291 TI's original RFFE wiring, hence I am now leaning toward this new approach. |