FreeCalypso > hg > freecalypso-reveng
comparison pirelli/vctcxo @ 195:ed7318a03e0c
pirelli/vctcxo: VCTCXO connections traced out
| author | Michael Spacefalcon <falcon@ivan.Harhan.ORG> |
|---|---|
| date | Sun, 11 Jan 2015 04:33:48 +0000 |
| parents | |
| children | cbd944ebeff0 |
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| 194:805e99848aea | 195:ed7318a03e0c |
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| 1 Let's trace the TCXOEN signal from the Calypso. Calypso ball A12, no trace | |
| 2 visible, guessing a micro-via right under the ball. L1 coord (3739,1053). | |
| 3 Guess appears right: on L2 there is a connection from a micro-via to an inner | |
| 4 via, the latter is at (3712,1055). Found it on L4: the via is in the middle of | |
| 5 a trace going both ways! Right branch goes to (4548,1028); left branch goes to | |
| 6 (1699,1349). | |
| 7 | |
| 8 Following the branch at (4548,1028): found it on L2, microvia back to L1 at | |
| 9 (4518,1048). Found it on L1, goes to some 2-pad footprint, can't tell if it's | |
| 10 unpopulated or a faint black resistor. The other end goes to a via at | |
| 11 (4676,919). Found it on L2, goes to inner via at (5135,684). Found it on L7, | |
| 12 goes to surface via at (5132,716). Found it on L8 - goes to flash RY/BY# ball | |
| 13 - WTF? | |
| 14 | |
| 15 Following the branch at (1699,1349): found it on L2, immediately goes back to | |
| 16 L1 at (1673,1353). Found it on L1, go to UL pad of the VCTCXO, passing by a | |
| 17 cap to GND. The cap is populated. | |
| 18 | |
| 19 Let's trace the signal from the VCTCXO to the Rita. VCTCXO pin is unknown, but | |
| 20 the input to Rita corresponds to a surface via at (2161,488) - at this point on | |
| 21 L1 there is an unpopulated cap(?) to GND and a series component (cap?) to the | |
| 22 actual Rita input. Found it on L2, goes back to L1 at (2123,1284). On L1 it | |
| 23 falls right into the UR pad of the VCTCXO! Conclusion: the signal from VCTCXO | |
| 24 to Rita passes through a single series component, just like in Rita datasheet. | |
| 25 | |
| 26 The LR pad of the VCTCXO is GND. Thus the control input must be the LL pad. | |
| 27 The input signal to here passes first through a series component, then passes | |
| 28 by a comp to ground, and then goes into the VCTCXO input. The entry point to | |
| 29 the whole arrangement is a surface via at (1669,1488). Found it on L2, inner | |
| 30 via at (1655,1467). Found it on L4, goes to (2932,855). Found it on L2, | |
| 31 surface via to L1 at (2950,837). That's Iota ball J4 (AFC), and there is also | |
| 32 a branch from there that goes to an unpopulated cap(?) footprint to GND. |