1 files changed, 26 insertions, 0 deletions
diff --git a/os/hal/dox/serial.dox b/os/hal/dox/serial.dox
index d4f2cf634..c2fae58f5 100644
--- a/os/hal/dox/serial.dox
+++ b/os/hal/dox/serial.dox
@@ -30,5 +30,31 @@
  * @pre     In order to use the SERIAL driver the @p HAL_USE_SERIAL option
  *          must be enabled in @p halconf.h.
  *
+ *
+ * @section serial_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).
+ * @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];
+
+    uninit [label="SD_UNINIT", style="bold"];
+    stop [label="SD_STOP\nLow Power"];
+    ready [label="SD_READY\nClock Enabled"];
+
+    uninit -> stop [label=" sdInit()"];
+    stop -> stop [label="\nsdStop()"];
+    stop -> ready [label="\nsdStart()"];
+    ready -> stop [label="\nsdStop()"];
+    ready -> ready [label="\nsdStart()"];
+    ready -> ready [label="\nAny I/O operation"];
+  }
+ * @enddot
+ *
  * @ingroup IO
  */