1.2.6.4.2 SRV_USI_Open Function

C

SRV_USI_HANDLE SRV_USI_Open( const SYS_MODULE_INDEX index )

Summary

Opens the specified USI service instance and returns a handle to it.

Description

This routine opens the specified USI service instance and provides a handle that must be provided to all other client-level operations to identify the caller and the instance of the service.

Precondition

Function SRV_USI_Initialize must have been called before calling this function.

Parameters

ParamDescription
indexIndex for the instance to be opened

Returns

If successful, the routine returns a valid open-instance handle (SRV_USI_HANDLE Typedef).

If an error occurs, the return value is SRV_USI_HANDLE_INVALID. Error can occur

  • if the specified instance has been already opened.
  • if the instance being opened is not initialized or is invalid.
  • if there is an error opening the serial interface (USB CDC instances only)

Example

SRV_USI_HANDLE handle;

handle = SRV_USI_Open(SRV_USI_INDEX_0);
if (handle == SRV_USI_HANDLE_INVALID)
{
    // Unable to open USI instance. Maybe it is not initialized
}

Remarks

The handle returned is valid until SRV_USI_Close is called.