# HG changeset patch # User Michael Spacefalcon # Date 1382244568 0 # Node ID fdfb57a1c5fe55c564704a302a5701d021177192 # Parent 037c9bea954c4dde66fdf3850524d3038e27a730 Pirelli PCB tracing: voice band i/f, MCSI and MODEM UART diff -r 037c9bea954c -r fdfb57a1c5fe pirelli/audio --- 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. diff -r 037c9bea954c -r fdfb57a1c5fe pirelli/mcsi --- /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. diff -r 037c9bea954c -r fdfb57a1c5fe pirelli/serial --- /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.