Swapping HEAD and DEVEL branches

[tinyos-2.x.git] / doc / txt / tep114.txt

diff --git a/doc/txt/tep114.txt b/doc/txt/tep114.txt
index 56e975914c8255cb33e7a1fb750c492c167e37fb..2d4b2bd83f6bbed3a951f8999c3ef2b8d326bb86 100644 (file)
--- a/doc/txt/tep114.txt
+++ b/doc/txt/tep114.txt
@@ -137,6 +137,13 @@ If the ``result`` parameter of the ``Read.readDone`` and
 ``ReadWrite.readDone`` events is not SUCCESS, then the memory of the
 ``val`` parameter MUST be filled with zeroes.
 
+If the call to ``Read.read`` has returned SUCCESS, but the
+``Read.readDone`` event has not yet been signalled, then a subsequent
+call to ``Read.read`` MUST not return SUCCESS. This simple locking
+technique, as opposed to a more complex system in which multiple
+read/readDone pairs may be outstanding, is intended to reduce the
+complexity of code that is a client of a SID interface.
+
 Examples of sensors that would be suited to this class of interface
 include many basic sensors, such as photo, temp, voltage, and ADC
 readings.