r5591 - trunk/gta02-core/docs/ecn

rehar at docs.openmoko.org rehar at docs.openmoko.org
Mon Aug 31 05:28:50 CEST 2009

Author: rehar
Date: 2009-08-31 05:28:50 +0200 (Mon, 31 Aug 2009)
New Revision: 5591

- added commit to ecn0010 and ecn0015
- removed ecn0020 from open ecn list
- added new ecn0036 "Removal of decoupling capacitor C3020"
- added new ecn0037 "Route ROUT1/LOUT1 back to LINE1/LINE2 input"
- added new ecn0038 "Loudspeaker EMI filter"

Modified: trunk/gta02-core/docs/ecn/STATUS
--- trunk/gta02-core/docs/ecn/STATUS	2009-08-30 22:31:30 UTC (rev 5590)
+++ trunk/gta02-core/docs/ecn/STATUS	2009-08-31 03:28:50 UTC (rev 5591)
@@ -35,6 +35,9 @@
 0033	Execute	Replace coupling capacitors for input/output lines
 0034	Discuss	Route additional SPI/GPIO pins to debug connector
 0035	Discuss Kill WLAN unused RF components
+0036    Discuss Removal of decoupling capacitor C3020
+0037    Discuss Route ROUT1/LOUT1 back to LINE1/LINE2 input
+0038    Discuss Loudspeaker EMI filter
 Open ECNs
@@ -48,7 +51,6 @@
 0017	BT
 0018	AUDIO
 0019	AUDIO
-0020	AUDIO
 0024	GPS
 0026	SD-SIM
 0027	General
@@ -57,3 +59,6 @@
 0032    AUDIO
 0033    AUDIO
 0034	IO
+0036    AUDIO
+0037    AUDIO
+0038    AUDIO

Modified: trunk/gta02-core/docs/ecn/ecn0010.txt
--- trunk/gta02-core/docs/ecn/ecn0010.txt	2009-08-30 22:31:30 UTC (rev 5590)
+++ trunk/gta02-core/docs/ecn/ecn0010.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -26,4 +26,4 @@
 Author: Rene Harder <rehar at saweb.de>
+Commit: SVN 5118

Modified: trunk/gta02-core/docs/ecn/ecn0015.txt
--- trunk/gta02-core/docs/ecn/ecn0015.txt	2009-08-30 22:31:30 UTC (rev 5590)
+++ trunk/gta02-core/docs/ecn/ecn0015.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -14,5 +14,6 @@
 Author: Rene Harder <rehar at saweb.de>
+Commit: SVN 5201
 Review: Werner Almesberger <werner at openmoko.org>, SVN 5490
 Commit: SVN 5528, Removed R4407/4405

Modified: trunk/gta02-core/docs/ecn/ecn0022.txt
--- trunk/gta02-core/docs/ecn/ecn0022.txt	2009-08-30 22:31:30 UTC (rev 5590)
+++ trunk/gta02-core/docs/ecn/ecn0022.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -21,5 +21,5 @@
 Author: Rene Harder <rehar at saweb.de>
-Commit: SVN 5188 ?
+Commit: SVN 5188
 Review: Werner Almesberger <werner at openmoko.org>, SVN5565

Added: trunk/gta02-core/docs/ecn/ecn0036.txt
--- trunk/gta02-core/docs/ecn/ecn0036.txt	                        (rev 0)
+++ trunk/gta02-core/docs/ecn/ecn0036.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -0,0 +1,9 @@
+Removal of decoupling capacitor C3020
+This capacitor is NC right now and there are no plans to change this.
+So we can remove C3020 to create more room for other components (audio rework).
+Author: Rene Harder <rehar at saweb.de>

Added: trunk/gta02-core/docs/ecn/ecn0037.txt
--- trunk/gta02-core/docs/ecn/ecn0037.txt	                        (rev 0)
+++ trunk/gta02-core/docs/ecn/ecn0037.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -0,0 +1,31 @@
+Route ROUT1/LOUT1 back to LINE1/LINE2 input
+In Joerg's GTA03 proposal he connected the stereo line from the headset jack
+back to the line inputs of the codec. So you are able to connect a line 
+compatible audio source to it and record or process the audio stream within the
+We need to connect the codec side of the coupling capacitors C4110 and C4411 
+trough a 1k series resistor (R3030/R3031) to the line input (LINE1 and LINE2)
+of the codec. To be within the standard of line compatible audio inputs we need
+to increase the input impedance to 10k Ohm for a low impedance input. Therefore
+we have to change R4416 and R4417 to at least 10k. 
+Note: In general the input impedance for a regular line input (high impedance)
+is around 47k Ohm. We cannot change R4416/4417 to 47k Ohm as required because 
+we need a proper pulldown for the jack insert detection. The voltage divider 
+is formed out of the codec's internal 100k Ohm pull-up the 10k Ohm series 
+resistance R4402 and the pulldown resistor R4116. If we increase R4416 to 47k 
+Ohm the low level voltage would be around 1.2V, the codec maximum low level is
+at 0.8V so we would not be able to generate an interrupt during jack insert.
+To use this feature you would still need a special (probably self made) adapter
+cable, because a 2.5mm audio jack is very uncommon for any audio equipment. 
+Author: Rene Harder <rehar at saweb.de>

Added: trunk/gta02-core/docs/ecn/ecn0038.txt
--- trunk/gta02-core/docs/ecn/ecn0038.txt	                        (rev 0)
+++ trunk/gta02-core/docs/ecn/ecn0038.txt	2009-08-31 03:28:50 UTC (rev 5591)
@@ -0,0 +1,17 @@
+Loudspeaker EMI filter
+To protect the codec from incoming interferences it would be more efficient to
+place the filter caps C4119-C4122 and C4128 on the codec side of the common 
+mode coke. So they act in combination with B4105 as a lowpass filter who 
+removes incoming RF on the audio lines. I also would combine R4119/20 and 
+R4121/22 (39pF+18pF) to one 47pF capacitor (like the EMI filter in the earpiece
+path) so we can remove at least one unique component from the BOM.
+To do:
+I do not see any particular reason why C4128 is 10pF it's there since GTA01.
+This needs to be clarified because this value is rarely used (vibrator) in GTA02
+schematics and might be worth replacing it.
+Author: Rene Harder <rehar at saweb.de> 

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