[doc][doxygen] Fix doxygen struct error.

Signed-off-by: supperthomas <[email protected]>

1 files changed, 13 insertions, 4 deletions

diff --git a/documentation/doxygen/kernel.h b/documentation/doxygen/kernel.h
index 15f6983e07..288688bfe6 100644
--- a/documentation/doxygen/kernel.h
+++ b/documentation/doxygen/kernel.h
@@ -32,10 +32,10 @@
  * round-robin scheduling is used for this case.
  * - The time of scheduler to choose the next highest ready thread is determinant.
  * - There are four status in thread management
- *	-# Initialization
- *	-# Running/Ready
- *	-# Blocked
- *	-# Closed
+ *  -# Initialization
+ *  -# Running/Ready
+ *  -# Blocked
+ *  -# Closed
  * - The number of threads in the system is unlimited, only related with RAM.
  */
 
@@ -96,6 +96,15 @@
  */
 
 /**
+ * @defgroup Signal Signal
+ * @brief signal is used for thread kill etc.
+ *
+ * A signal (also known as a soft interrupt signal), from a software perspective,
+ * is a simulation of interrupt mechanism. When it comes to its principle,
+ * thread receiving a signal is similar to processor receiving an interrupt request.
+ */
+
+/**
  * @defgroup MM Memory Management
  * @brief memory management for memory pool and heap memory
  *