1.2.6.4.11 SRV_USI_HANDLE_INVALID Macro
C
#define SRV_USI_HANDLE_INVALID (((SRV_USI_HANDLE) -1))
Summary
Definition of invalid USI handle.
Description
This definition is used to indicate that an USI handle (SRV_USI_HANDLE Typedef) is invalid. SRV_USI_Open returns this value if:
the specified instance has been already opened.
the instance being opened is not initialized or is invalid.
if there is an error opening the serial interface (USB CDC instances only)
Remarks
The handle returned from SRV_USI_Open should be checked to ensure it is different to SRV_USI_HANDLE_INVALID before attempting to call any other USI routine using the handle.