DMA max size

[lpcware]

Content originally posted in LPCWare by guillaumeL on Mon Apr 28 11:49:00 MST 2014
Hi everybody,

  I'm working with an LPC1769 and I use a DMA to transfert data from SPI to memory. I have a question concerning the maximum data size I can allocate for the DMA transfert. Is it limited or I can allocate a buffer of 1kbyte to transfer data?

Thanks,
Guillaume

[lpcware]

Content originally posted in LPCWare by Pacman on Mon Apr 28 13:08:53 MST 2014
1KByte is very small. The LPC1769 can easily transfer a buffer of that size in a single LLI.
The transfer-size is 12-bit, which means 4096 units, where a unit can be a byte, halfword or word.
That means: Your maximum transfer size would be 4096 if you're using bytes.
-But as you can make a Linked List, there's no real limit to how many bytes you can transfer.

See UM10360, section 31.6.5 "Scatter/gather" for more information on Linked List Items (LLI).