Kinetis Design StudioのトピックWhy does the user need to provide DeviceData in every Processor Expert LDD API call?

Why does the user need to provide DeviceData in every Processor Expert LDD API call?

stephenlangstaf — Sun, 06 Jul 2014 18:40:19 GMT

If I create an instance of a driver using Processor Expert, why do I have to pass a DeviceData pointer into the API?

For example, if I create a component for the blue LED on my FRDM-KL25Z board named 'LED_BLUE' and of type 'BitIO_LDD', files are created called 'LED_BLUE.c' and 'LED_BLUE.h' and the API functions are prefixed by the name LED_BLUE (e.g. LED_BLUE_Init(), LED_BLUE_PutVal()).

I would have thought that this would be enough context for the component to know what object we are talking about without also having to pass LED_BLUE_DeviceData as the first parameter of each function.

Couldn't the component store a reference to its own DeviceData? Is there something I am missing?

Re: Why does the user need to provide DeviceData in every Processor Expert LDD API call?

Jorge_Gonzalez — Sun, 06 Jul 2014 22:17:48 GMT

Hello Stephen:

Some components require this DeviceData pointer to maintain portability or RTOS compatibility, since this handler stores configuration parameters, component status, events, etc.

However in the case of BitIO_LDD, you are correct that this is a weakness of Processor Expert generated code. Colleague Erich Styger suggests a workaround in his blog:

Optimized BitIO_LDD Programming with Processor Expert | MCU on Eclipse

Regards!

Jorge_Gonzalez

Re: Why does the user need to provide DeviceData in every Processor Expert LDD API call?

stephenlangstaf — Mon, 07 Jul 2014 09:28:40 GMT

Thanks Jorge,

I see now there is a high(er) level driver 'BitIO' that wraps the 'BitIO_LDD' driver calls, providing the useless DeviceData pointer so I don't have to.

Thanks again,

Steve.