r5695 - trunk/gta02-core/docs/ecn

[werner at docs.openmoko.org]

Author: werner
Date: 2009-10-19 14:30:19 +0200 (Mon, 19 Oct 2009)
New Revision: 5695

Modified:
   trunk/gta02-core/docs/ecn/STATUS
   trunk/gta02-core/docs/ecn/ecn0010.txt
Log:
Various ECN0010 updates:

- use IO_3V3 to feed LDO34IN (CODEC_3V3 and IO_2V8)
- rename CODEC_3V3, i.e., to CODEC_VDD
- add 0R to LDO34IN, so that we can switch to Vsys if 3 V are not enough
- moved to "Execute"



Modified: trunk/gta02-core/docs/ecn/STATUS
===================================================================
--- trunk/gta02-core/docs/ecn/STATUS	2009-10-17 22:40:48 UTC (rev 5694)
+++ trunk/gta02-core/docs/ecn/STATUS	2009-10-19 12:30:19 UTC (rev 5695)
@@ -9,7 +9,7 @@
 0007	Done	Remove KEEPACT net and connect PMU.KEEPACT directly to IO_3V3
 0008	Execute	Remove external GPS antenna connector and circuit (CON7602)
 0009	Done	Remove LED transistors (Q1501 and Q1502)
-0010	Discuss	Remove audio amplifier (U4101)
+0010	Execute	Remove audio amplifier (U4101)
 0011	Execute	Reduce number of varistors on USB_VBUS (C4902, C4909)
 0012	Defer	Add fuse to USB_VBUS
 0013	Defer	Increase rated current of B4902

Modified: trunk/gta02-core/docs/ecn/ecn0010.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0010.txt	2009-10-17 22:40:48 UTC (rev 5694)
+++ trunk/gta02-core/docs/ecn/ecn0010.txt	2009-10-19 12:30:19 UTC (rev 5695)
@@ -40,6 +40,14 @@
 would have to operate at 3.05 V or less, due to the 250 mV voltage drop
 of the LDO.) [3]
 
+Compromise: connect LDO34IN via a 0R to IO_3V3, so we can rework to
+using Vsys (e.g., by running a wire from the SYS1/SYS2 end of C1767),
+if this should turn out to be necessary.
+
+Since CODEC_3V3 now has a worst-case drop of 250 mV from 3.3 V, we
+should rename it to CODEC_3V or, perhaps better, CODEC_VDD. (And add
+a comment stating the nominal voltage of 3 V.)
+
 [1] http://www.wolfsonmicro.com/uploads/documents/en/WM8753.pdf
 [2] http://lists.openmoko.org/pipermail/gta02-core/2009-October/000744.html
 [3] http://lists.openmoko.org/pipermail/gta02-core/2009-October/000746.html