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authorMarti Bolivar <mbolivar@leaflabs.com>2011-05-27 18:55:57 -0400
committerMarti Bolivar <mbolivar@leaflabs.com>2011-05-27 18:55:57 -0400
commiteee36ecb65ec8d8e032886468e22d941cc3239c9 (patch)
tree4adcbffd7707ef41894921ddbb3510e4ce601052
parent9595ce520a6be0d993e87d80bed9fc47e7c203ba (diff)
downloadlibrambutan-eee36ecb65ec8d8e032886468e22d941cc3239c9.tar.gz
librambutan-eee36ecb65ec8d8e032886468e22d941cc3239c9.zip
Docs: Correct i2c.rst errors.
10-bit addressing has now been implemented. Slave mode is unimplemented, however.
-rw-r--r--docs/source/i2c.rst21
1 files changed, 11 insertions, 10 deletions
diff --git a/docs/source/i2c.rst b/docs/source/i2c.rst
index 31976ac..8f1b26f 100644
--- a/docs/source/i2c.rst
+++ b/docs/source/i2c.rst
@@ -7,17 +7,18 @@
two wires/channels for communication between many devices. Every
message passed on the bus is between a *master* (who initiates the
message) and a *slave* device. Slaves are addressed using 7-bit
-addresses (up to 127 unique devices); 10-bit addressing is possible,
-but currently unimplemented. Every message consists of an arbitrary
-combination of 8-bit reads and writes as requested by the master.
-Higher level functionality, such as reading a particular register
-value, is achieved by writing to set the memory location then reading
-to pull out the data.
+addresses (up to 127 unique devices); 10-bit addressing is also
+possible. Every message consists of an arbitrary combination of 8-bit
+reads and writes as requested by the master. Higher level
+functionality, such as reading a particular register value, is
+achieved by writing to set the memory location then reading to pull
+out the data.
Note that the master/slave designation is on a message-by-message
basis. Maple can act as both a master (messages initiated by user
code) and slave device (responding to requests via configurable
-interrupt handlers) at the same time.
+interrupt handlers) at the same time (though slave mode is currently
+unimplemented).
.. contents:: Contents
:local:
@@ -28,10 +29,10 @@ Hardware/Circuit Design
.. FIXME [0.1.0] Link to board-specific values (BOARD_I2C1_SDA_PIN, etc.)
Maple boards have two |i2c| ports. Maples reliably communicate with
-up to a 400kHz clock speed; this doesn't translate into a 400kbps data
-rate except in extreme cases because of addressing and protocol
+up to a 400kHz clock speed; this doesn't translate into a 400kbps
+data rate except in extreme cases because of addressing and protocol
overhead. We have tested clock speeds up to a megahertz and have had
-mixed results; in theory it could be possible to achieve even higher
+mixed results; in theory, it could be possible to achieve even higher
rates, but signal quality degrades rapidly, and the bus becomes
unreliable.