FreeCalypso > hg > freecalypso-reveng
comparison pirelli/spca @ 54:8e4dac492552
another Pirelli PCB tracing session, focusing on the display subsystem
| author | Michael Spacefalcon <msokolov@ivan.Harhan.ORG> |
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| date | Sun, 28 Jul 2013 21:38:07 +0000 |
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| 53:00dedefbdfd1 | 54:8e4dac492552 |
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| 1 Tracing signal from Calypso A1 (address line 1, ball F2); expecting to see it go | |
| 2 to ball H8 on SPCA552E. On L1 the trace goes to (4326,756). On L2 I see it | |
| 3 branching - d'oh, it's address line A1, of course it will go to a ton of things! | |
| 4 Looking for another signal to trace that would be point-to-point from Calypso | |
| 5 to SPCA552E. | |
| 6 | |
| 7 Let's try tracing the bypass GPIO signal, presumably originating from GPIO 7 on | |
| 8 the Calypso. That's Calypso ball N2. L1 goes to (4259,467). L2 takes it to an | |
| 9 inner via at (4290,471). Found it on L5: goes to another inner via at | |
| 10 (4370,1835). Found it on L7: goes to (4270,2026). On L8 it arrives at an SPCA | |
| 11 ball which we are going to assume is A8 (bypass input according to the Nokia | |
| 12 schematic). | |
| 13 | |
| 14 Deduced SPCA552E BGA orientation in steve-m's L8 picture: A1 in the LL corner, | |
| 15 row A along the bottom. | |
| 16 | |
| 17 Accessible surface test points around the SPCA: | |
| 18 | |
| 19 * Along the bottom (the side toward the red and # keys) we have TPs for A8 | |
| 20 (bypass input) and C7 (Rxd1). The TP in between these two seems to be connected | |
| 21 through some inner layer, haven't traced yet. The L8 coordinates of this TP are | |
| 22 (4221,2119). The hole seems to be slanted to (4228,2112) though. | |
| 23 On L7 it goes to a large-looking via at (4196,1966). | |
| 24 | |
| 25 * On the side toward the antenna we have TPs for C2 (LcmCs) and D3 (LcmWr). | |
| 26 | |
| 27 * On the side toward the USB port we have TPs for J8 (Txd1) and H9 (HstRd_n). | |
| 28 | |
| 29 * On the side toward the green and * keys we have TPs for G4 (Suspend), | |
| 30 H5 (Trap), and J7 (LcmVs). | |
| 31 | |
| 32 The L8 trace from ball H6 (LcmMck) goes in two directions, terminating at via | |
| 33 points (4066,1704) and (4270,1251). On L7 the leg from (4066,1704) goes to | |
| 34 (3722,1700), looks like a micro-via back to L8. | |
| 35 | |
| 36 Tracing Calypso PWL signal, starting with Calypso ball L7. On L1 the trace from | |
| 37 ball L7 appears to go to (3988,528); the trace from ball K7 (PWT/BU, no other | |
| 38 functions listed in CAL000) goes to (4041,813). | |
| 39 | |
| 40 Tracing the mysterious PWT/BU first. On L2 the trace from (4041,813) goes to | |
| 41 (4211,1018), seems to be a micro-via back to L1. On L1 it goes to some strange | |
| 42 component pad at (4300,1186). The component seems to be a resistor; the other | |
| 43 side connection is unclear. | |
| 44 | |
| 45 Back to PWL. On L2 the trace from (3988,528) goes to a larger via at | |
| 46 (4010,554). Found in on L7: goes to a micro-via to L8 at (3975,478). On L8 it | |
| 47 goes to another via back to L7 at (3784,664). On L7 it goes to a larger via at | |
| 48 (3635,839). Found it on L5: goes to another via at (3512,1808). Found it on | |
| 49 L7: goes to a micro-via to L8 at (3459,1756). There it appears to connect to | |
| 50 the mysterious A3-90E component through some resistors. |