r5448 - trunk/gta02-core/docs/ecn

werner at docs.openmoko.org werner at docs.openmoko.org
Sat Aug 15 01:32:47 CEST 2009


Author: werner
Date: 2009-08-15 01:32:47 +0200 (Sat, 15 Aug 2009)
New Revision: 5448

Added:
   trunk/gta02-core/docs/ecn/ecn0028.txt
Modified:
   trunk/gta02-core/docs/ecn/STATUS
   trunk/gta02-core/docs/ecn/ecn0025.txt
Log:
- ECN0025 moves to Done. First one to cross the finishing line.
- added ECN0028, proposing removal of U4905



Modified: trunk/gta02-core/docs/ecn/STATUS
===================================================================
--- trunk/gta02-core/docs/ecn/STATUS	2009-08-14 23:16:40 UTC (rev 5447)
+++ trunk/gta02-core/docs/ecn/STATUS	2009-08-14 23:32:47 UTC (rev 5448)
@@ -24,6 +24,7 @@
 0022	Discuss	Apply bass fix
 0023	Edit	Fix #1024 (C1009)
 0024	Edit	Improve GPS ground and PCB layout
-0025	Discuss	Connect CLKOUT1 to UEXTCLK (U1501)
+0025	Done	Connect CLKOUT1 to UEXTCLK (U1501)
 0026	Discuss	Improve bus termination at sd-card
 0027	Edit	Renamed some nets for clarity
+0028	Edit	Remove USB host power switch

Modified: trunk/gta02-core/docs/ecn/ecn0025.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0025.txt	2009-08-14 23:16:40 UTC (rev 5447)
+++ trunk/gta02-core/docs/ecn/ecn0025.txt	2009-08-14 23:32:47 UTC (rev 5448)
@@ -12,3 +12,4 @@
 Author: Rask Ingemann Lambertsen <ccc94453 at vip.cybercity.dk>
 Review: Dave Ball <openmoko at daveball.org.uk>, rev5338.
 Commit: SVN 5339, Connect CLKOUT1 to UEXTCLK
+Review: Werner Almesberger <werner at openmoko.org>, SVN 5447

Added: trunk/gta02-core/docs/ecn/ecn0028.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0028.txt	                        (rev 0)
+++ trunk/gta02-core/docs/ecn/ecn0028.txt	2009-08-14 23:32:47 UTC (rev 5448)
@@ -0,0 +1,23 @@
+Remove USB "charge path" power switch U4905
+
+
+We can just disable USB host power at the PMU, so U4905 has no real
+purpose. Note that an overvoltage-limiting component should be used in
+the future, as explained in ECN0014.
+
+Hardware changes:
+
+- remove U4905
+- eliminate net USB_VBUS and just call it VBUS (i.e., merge the two)
+- remove C4911, C4913, R4920
+- remove C4909 (see also ECN0011)
+- keep R1918 but move it to the up-converter delivering host mode power
+- eliminate net nUSB_OC, freeing GPG9
+
+Software changes:
+
+- when switching to USB host mode, make sure the PMU MBC is in USB
+  suspend mode (MBCC7.usbdevstat = 3)
+
+
+Author: Werner Almesberger <werner at openmoko.org>




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