Using SSC or SPI with high data rates

NETMF & Gadgeteer
21

wow, perfect.
Just found a note, that it is not allowed to store data pointers in RLP domain, cause the GC will rearrange the memory.

But as there is a possibility to pin down some memory area, I can do as I done before, ring-buffer and here we go. Same as your solution, only with the ability to have more than one buffer, if needed.

Thanks for that important Input.

With best regards

Gerhard

22

@ Gerhard - if you use the InvokeEx method to call a native function, and pass the buffer as the first parameter, the buffer will be passed as a pointer, and not copied. This pointer will still be valid after the native function returns control to managed code. This only works if the managed buffer is allocated as a static byte buffer.

Static variables are not garbage collected in .Net.

http://social.msdn.microsoft.com/Forums/en-US/ed05d414-9864-4093-b200-67dede4b46e1/garbage-collection-and-static-classes

See my RLP music driver in Code Share:

https://www.ghielectronics.com/community/codeshare/entry/805

23

@ jasdev - are you sure that compaction will not move the buffer?

24

@ Gus - No, I’m not 100% sure. I’ve not been able to find a definitive answer from Microsoft. However, I did find other sources that seem to confirm that this is true, and I tested my RLP music driver for many hours, and never encountered an error due to the buffer being moved.