--- a/pirelli/audio	Fri Aug 02 02:16:31 2013 +0000
+++ b/pirelli/audio	Sun Oct 20 04:49:28 2013 +0000
@@ -17,3 +17,24 @@
 Found them on L7: fat traces to micro-vias at (3870,934) and (3898,869).
 Finally on L8 they go to the Winbond chip!  The speaker connection pins appear
 to be the two leftmost ones in the top row of 9 pins.
+
+Calypso-Iota Voice Band interface
+
+Tracing the Calypso voice output signal, starting from Calypso ball P14 (VDX).
+On L1 it goes to a via at (3401,429).  On L2 it branches: one end goes to
+(3366,304) - suspected via back to L1 for a test point, and the other end goes
+to (2885,917) - also a suspected via back to L1.  Found the 1st branch on L1:
+it's a short trace to another via at (3291,304).  Found the 2nd branch on L1
+too: it goes to Iota ball F5 (VDR), matching the Leonardo schematics.
+
+Now let's trace the branch that went to (3291,304) on L1.  On L2 it goes to a
+short trace that goes to (3349,197) - suspected micro-via back to L1.  Looking
+on L1: yes, indeed the trace seems to lead back here, but then the edge
+grind-down damage gets in the way.  Looking at the L1 populated photo, the
+trace definitely seems to go to an exposed test point.
+
+The apparent lack of a switch or MUX on the Iota digital voice input strongly
+suggests that in Wi-Fi VoIP operation the Calypso DSP acts as a forwarder for
+the digital voice samples, which are being fed to it from the VoIP chip via
+another interface: MCSI, or perhaps the otherwise unused MODEM UART switched
+over to DSP ownership.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pirelli/mcsi	Sun Oct 20 04:49:28 2013 +0000
@@ -0,0 +1,15 @@
+Tracing all 4 MCSI signals starting from the Calypso
+
+MCSI_TxD: Calypso ball L10, L1 trace goes to (3829,474).  The trace on L2 gets
+lost in the edge grind-down damage.
+
+MCSI_RxD: Calypso ball M10, no visible trace on L1 - perhaps there is a
+micro-via under the ball?  The ball pad coords are (3841,499).  Looking at L2,
+the micro-via hypothesis seems to be correct: a trace from those coords goes in
+the same bunch as the MCSI_TxD.  But then it gets lost in the damage too.
+
+MCSI_CLK: Calypso ball N10, L1 trace goes to (3898,369).  L2: joins the same
+bunch with MCSI_TxD and MCSI_RxD, then gets lost in the damage.
+
+MCSI_FSYNCH: Calypso ball K9, L1 trace goes to (3865,524).  L2: same story as
+the others.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pirelli/serial	Sun Oct 20 04:49:28 2013 +0000
@@ -0,0 +1,11 @@
+Tracing the apparently-unused MODEM UART signals
+
+TxD from Calypso: ball B9, L1 trace goes to (3905,1100).  Found it on L2, goes
+to an inner via at (3914,1070).  Found the inner via on L7, goes to (3182,1071).
+On L8 the signal goes directly to the debug connector identified by steve-m.
+
+RxD to Calypso: ball A9, seems to have a micro-via under the ball, pad coords
+(3888,1054).  Found it on L2, goes to an inner via at (3911,1030) and also to
+what looks like a via back to L1 at (3858,1228).  The stub back to L1 appears
+to be a pull-up resistor.  Found the inner via on L7, goes to (3154,928).
+On L8 the signal goes directly to the debug connector identified by steve-m.