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authorMarti Bolivar <mbolivar@leaflabs.com>2011-08-16 06:11:25 -0400
committerMarti Bolivar <mbolivar@leaflabs.com>2011-08-16 06:11:25 -0400
commitb49dfa32cc38e7a8a708261a03ed0d8ce69f7feb (patch)
tree09dc5e5bcf6bba4a84e6a56d9f31d411ee354a66 /source
parent1529927c59ee12f390bec9eb612343a982e1f43c (diff)
downloadlibrambutan-b49dfa32cc38e7a8a708261a03ed0d8ce69f7feb.tar.gz
librambutan-b49dfa32cc38e7a8a708261a03ed0d8ce69f7feb.zip
usart: Add electrical configuration removed from serial.rst.
Diffstat (limited to 'source')
-rw-r--r--source/usart.rst13
1 files changed, 11 insertions, 2 deletions
diff --git a/source/usart.rst b/source/usart.rst
index e65821d..fa9c55c 100644
--- a/source/usart.rst
+++ b/source/usart.rst
@@ -10,11 +10,17 @@ another Maple, etc.).
.. contents:: Contents
:local:
+.. _usart-circuit:
+
Hardware/Circuit Design
-----------------------
-.. TODO [0.0.12] Add some more information here (like how you should
-.. connect TX_a to RX_b and RX_a to TX_b).
+To use a serial port to communicate with an external serial device,
+connect the TX pin to your device's RX pin, the RX to your device's TX
+pin, and your Maple board's ground to your device's ground.
+
+.. warning:: Don't connect these pins directly to an RS232 serial
+ port; they operate at +/- 12V and can damage your board.
.. TODO [0.0.12/Maple Native] UART4 and UART5, Native links
@@ -52,3 +58,6 @@ Recommended Reading
* ST `Reference Manual RM0008
<http://www.st.com/stonline/products/literature/rm/13902.pdf>`_
(PDF), Chapter 27.
+* `Serial and UART Tutorial
+ <http://www.freebsd.org/doc/en/articles/serial-uart/>`_ (written for
+ FreeBSD, but contains a large amount of general information).