1 files changed, 34 insertions, 6 deletions
diff --git a/os/hal/dox/i2c.dox b/os/hal/dox/i2c.dox
index 1ffd2da47..83dcfe285 100644
--- a/os/hal/dox/i2c.dox
+++ b/os/hal/dox/i2c.dox
@@ -22,7 +22,16 @@
  * @defgroup I2C I2C Driver
  * @brief   Generic I2C Driver.
  * @details This module implements a generic I2C (Inter-Integrated Circuit)
- *          driver.
+ *          driver. On STM32 platform you can choose method of waiting START
+ *          and STOP bits: polling wait or wait using GPT. GPT method use
+ *          one timer per I2C interface, on the other hand -- polling is
+ *          block function that starts transfer.
+ * @note    If you decide to use polling wait -- do NOT start transmit or
+ *          receive from callback because it run in ISR context.
+ * @note    You must set I2C interrupts priority to highest level in the
+ *          system. 
+ * @note    If you use GPT than set GPT interrupts priority level over I2C
+ *          interrupts priority level.
  * @pre     In order to use the I2C driver the @p HAL_USE_I2C option
  *          must be enabled in @p halconf.h.
  *
@@ -31,12 +40,31 @@
  * 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
- * @else
- * @endif
- *
+ * @dot
+  digraph example {
+    rankdir="LR";
+    node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="false",
+          width="0.9", height="0.9"];
+    edge [fontname=Helvetica, fontsize=8];
+
+    uninit [label="I2C_UNINIT", style="bold"];
+    stop [label="I2C_STOP\nLow Power"];
+    ready [label="I2C_READY\nClock Enabled"];
+    active_tx [label="I2C_ACTIVE_TRANSMIT\nBus TX Active"];
+    active_rx [label="I2C_ACTIVE_RECEIVE\nBus RX Active"];
+
+    uninit -> stop [label="i2cInit()"];
+    stop ->   stop [label="i2cStop()"];
+    stop ->   ready [label="i2cStart()"];
+    ready ->  active_tx [label="i2cMasterTransmit()"];
+    ready ->  active_rx [label="i2cMasterReceive()"];
+    active_tx -> ready [label="_i2c_isr_code()"];
+    active_rx -> ready [label="_i2c_isr_code()"];
+    ready ->  stop [label="i2cStop()"];
+  }
+ * @enddot
  * The driver is not thread safe for performance reasons, if you need to access
- * the I2C bus from multiple thread then use the @p i2cAcquireBus() and
+ * the I2C bus from multiple threads then use the @p i2cAcquireBus() and
  * @p i2cReleaseBus() APIs in order to gain exclusive access.
  *
  * @ingroup IO