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[web/altusmetrum] / TeleMetrum / index.mdwn

diff --git a/TeleMetrum/index.mdwn b/TeleMetrum/index.mdwn
index a7f4abab5d687847cc11bf3096e22864dea106d0..d5ed480c36fb2af66cbb491b0ab890dd80a651ca 100644 (file)
--- a/TeleMetrum/index.mdwn
+++ b/TeleMetrum/index.mdwn
@@ -99,12 +99,13 @@ always want GPS on board, which lead to our current second generation boards.
        * 128k x 8
        * SPI interface
 * [Microchip MCP9700A](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027103) discrete temperature sensor
-       * eliminated in v0.2 to free GPIO line for companion interface
 * used 1000uF electrolytic capacitor charged to 5V for pyro supply
 * two LEDs instead of one attached to CPU
-       * eliminated second LED to free GPIO line for companion interface
 
-## [Production History](production) ##
+The elimination of the discrete temperature sensor and second LED were
+necessary to support the companion board interface added in v0.2.
+
+## [Production History](../production) ##
 
 ## [Flight Logs](flightlogs) ##
 
@@ -117,6 +118,12 @@ always want GPS on board, which lead to our current second generation boards.
   place parts!  Without an inspection microscope, loading and testing these
   boards might be impossible.
 
+* The addition of on-board GPS in v0.2 means that the total power consumption
+  can exceed the rate at which we draw power from the USB interface, 
+  particularly when the GPS is in cold start mode.  This means a battery must 
+  be attached during operation, and also that the battery will only charge 
+  effectively from USB when the board is turned off.
+
 * The v0.1 artwork had three issues, two of which required physical rework
   on each board.  All of these issues were fixed in v0.2.