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diff --git a/docs/source/i2c.rst b/docs/source/i2c.rst deleted file mode 100644 index 670b91d..0000000 --- a/docs/source/i2c.rst +++ /dev/null @@ -1,77 +0,0 @@ -.. _i2c: - -|i2c| -===== - -|i2c| is a crude and easy-to-hack serial protocol that requires only -two wires/channels for communication between Maple and many other -devices. - -.. contents:: Contents - :local: - -Overview --------- - -Communication via |i2c| is broken up into messages. Every message is -between a *master* device, which initiates the message, and a *slave* -device, which responds. - -Slaves are addressed using 7-bit 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 (though slave mode is currently -unimplemented). - -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 -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 -rates, but signal quality degrades rapidly, and the bus becomes -unreliable. - -Proper wiring and pull-up resistor selection are essential when -incorporating |i2c| into a circuit, especially with data rates above -100kHz. In the lab, we usually use approximately 5kΩ resistors with -|vcc| (3.3V) as the high voltage, and try to connect the pullup -voltage as close to the SDA and SCL pins as possible. We recommend -looking at the ST reference website for |i2c| (see the -:ref:`recommended reading <i2c-recommended-reading>` below), starting -with a slow clock rate (10kHz), and, if possible, using an -oscilloscope to debug any issues. - -Function Reference ------------------- - -Currently, only low-level support in :ref:`libmaple-i2c` exists. A -Wiring-style library is planned for a future release. - -SMBus ------ - -The STM32 microcontroller has hardware support for SMBus, but software -for it is not yet implemented. - -.. _i2c-recommended-reading: - -Recommended Reading -------------------- - -* `I2C Bus <http://www.i2c-bus.org/>`_ -* `Wikipedia: I2C <http://en.wikipedia.org/wiki/I%C2%B2C>`_ -* `Arduino I2C/TWI reference <http://www.arduino.cc/playground/Learning/I2C>`_ -* ST `Application Note on Advanced I2C Usage - <http://www.st.com/stonline/products/literature/an/15021.pdf>`_ (PDF) |