doc: I2C, add more documentation for old API backends.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4462 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/drv/i2c.h b/bertos/drv/i2c.h
index 7e43c63bd8ca00b0f8a727c7b5f18184cf648016..7f7e454547618c71492a55796b10b340c51d1d66 100644 (file)
--- a/bertos/drv/i2c.h
+++ b/bertos/drv/i2c.h
@@ -452,11 +452,12 @@ INLINE int i2c_error(I2c *i2c)
 
 /**
  * \ingroup old_i2c_api
- * I2C Backends.
+ * \name I2C Backends.
  * Sometimes your cpu does not have a builtin
  * i2c driver or you don't want, for some reason, to
  * use that.
  * With this you can choose, at compile time, which backend to use.
+ * Set the CONFIG_I2C_BACKEND configuration variable in cfg_i2c.h
  * @{
  */
 #define I2C_BACKEND_BUILTIN 0 ///< Uses cpu builtin i2c driver