Tracing signal from Calypso A1 (address line 1, ball F2); expecting to see it go
to ball H8 on SPCA552E.  On L1 the trace goes to (4326,756).  On L2 I see it
branching - d'oh, it's address line A1, of course it will go to a ton of things!
Looking for another signal to trace that would be point-to-point from Calypso
to SPCA552E.

Let's try tracing the bypass GPIO signal, presumably originating from GPIO 7 on
the Calypso.  That's Calypso ball N2.  L1 goes to (4259,467).  L2 takes it to an
inner via at (4290,471).  Found it on L5: goes to another inner via at
(4370,1835).  Found it on L7: goes to (4270,2026).  On L8 it arrives at an SPCA
ball which we are going to assume is A8 (bypass input according to the Nokia
schematic).

Deduced SPCA552E BGA orientation in steve-m's L8 picture: A1 in the LL corner,
row A along the bottom.

Accessible surface test points around the SPCA:

* Along the bottom (the side toward the red and # keys) we have TPs for A8
(bypass input) and C7 (Rxd1).  The TP in between these two seems to be connected
through some inner layer, haven't traced yet.  The L8 coordinates of this TP are
(4221,2119).  The hole seems to be slanted to (4228,2112) though.
On L7 it goes to a large-looking via at (4196,1966).

* On the side toward the antenna we have TPs for C2 (LcmCs) and D3 (LcmWr).

* On the side toward the USB port we have TPs for J8 (Txd1) and H9 (HstRd_n).

* On the side toward the green and * keys we have TPs for G4 (Suspend),
  H5 (Trap), and J7 (LcmVs).

The L8 trace from ball H6 (LcmMck) goes in two directions, terminating at via
points (4066,1704) and (4270,1251).  On L7 the leg from (4066,1704) goes to
(3722,1700), looks like a micro-via back to L8.

Tracing Calypso PWL signal, starting with Calypso ball L7.  On L1 the trace from
ball L7 appears to go to (3988,528); the trace from ball K7 (PWT/BU, no other
functions listed in CAL000) goes to (4041,813).

Tracing the mysterious PWT/BU first.  On L2 the trace from (4041,813) goes to
(4211,1018), seems to be a micro-via back to L1.  On L1 it goes to some strange
component pad at (4300,1186).  The component seems to be a resistor; the other
side connection is unclear.

Back to PWL.  On L2 the trace from (3988,528) goes to a larger via at
(4010,554).  Found in on L7: goes to a micro-via to L8 at (3975,478).  On L8 it
goes to another via back to L7 at (3784,664).  On L7 it goes to a larger via at
(3635,839).  Found it on L5: goes to another via at (3512,1808).  Found it on
L7: goes to a micro-via to L8 at (3459,1756).  There it appears to connect to
the mysterious A3-90E component through some resistors.