i2c.dox
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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @defgroup I2C I2C Driver
* @brief Generic I2C Driver.
* @details This module implements a generic I2C (Inter-Integrated Circuit)
* driver.
* @pre In order to use the I2C driver the @p HAL_USE_I2C option
* must be enabled in @p halconf.h.
*
* @section i2c_1 Driver State Machine
* The driver implements a state machine internally, not all the driver
* functionalities can be used in any moment, any transition not explicitly
* shown in the following diagram has to be considered an error and shall
* be captured by an assertion (if enabled).
* @if LATEX_PDF
* @dot
digraph example {
size="5, 7";
rankdir="LR";
node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true",
width="0.9", height="0.9"];
edge [fontname=Helvetica, fontsize=8];
stop [label="I2C_STOP\nLow Power"];
uninit [label="I2C_UNINIT", style="bold"];
ready [label="I2C_READY\nClock Enabled"];
active_tx [label="I2C_ACTIVE_TX\nBus TX Active"];
active_rx [label="I2C_ACTIVE_RX\nBus RX Active"];
locked [label="I2C_LOCKED\nBus Locked"];
uninit -> stop [label="i2cInit()", constraint=false];
stop -> stop [label="i2cStop()"];
stop -> ready [label="i2cStart()"];
ready -> ready [label="i2cStart()"];
ready -> stop [label="i2cStop()"];
ready -> active_tx [label="i2cMasterTransmit()"];
ready -> active_rx [label="i2cMasterReceive()"];
active_tx -> ready [label="completed"];
active_rx -> ready [label="completed"];
active_tx -> locked [label="RDY_TIMEOUT"];
active_rx -> locked [label="RDY_TIMEOUT"];
locked -> stop [label="i2cStop()"];
locked -> ready [label="i2cStart()"];
}
* @else
* @dot
digraph example {
rankdir="LR";
node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true",
width="0.9", height="0.9"];
edge [fontname=Helvetica, fontsize=8];
stop [label="I2C_STOP\nLow Power"];
uninit [label="I2C_UNINIT", style="bold"];
ready [label="I2C_READY\nClock Enabled"];
active_tx [label="I2C_ACTIVE_TX\nBus TX Active"];
active_rx [label="I2C_ACTIVE_RX\nBus RX Active"];
locked [label="I2C_LOCKED\nBus Locked"];
uninit -> stop [label="i2cInit()", constraint=false];
stop -> stop [label="i2cStop()"];
stop -> ready [label="i2cStart()"];
ready -> ready [label="i2cStart()"];
ready -> stop [label="i2cStop()"];
ready -> active_tx [label="i2cMasterTransmit()"];
ready -> active_rx [label="i2cMasterReceive()"];
active_tx -> ready [label="completed"];
active_rx -> ready [label="completed"];
active_tx -> locked [label="RDY_TIMEOUT"];
active_rx -> locked [label="RDY_TIMEOUT"];
locked -> stop [label="i2cStop()"];
locked -> ready [label="i2cStart()"];
}
* @enddot
* @endif
* The driver is not thread safe for performance reasons, if you need to access
* the I2C bus from multiple threads then use the @p i2cAcquireBus() and
* @p i2cReleaseBus() APIs in order to gain exclusive access.
*
* @ingroup IO
*/