Using SCT to request a gpio (memory) to memory transfer.....

[lpcware]

Content originally posted in LPCWare by lpc_guy469 on Fri Apr 04 12:01:34 MST 2014
Hello all...


I would like to use SCT state machine events to trigger DMA transfers, i.e. reading a byte from a GPIO port (memory) and writing it to SRAM (memory).  In this example, I would prefer the source address (GPIO port) to remain the same but have the destination address (memory) increment.

After some investigation, I am beginning to believe that a memory-to-memory DMA transfer that is initiated (or controlled) by an SCT event will have to be done via an SCT interrupt....not via a DMA request!  It appears that issuing a DMA request (0 or 1) from an SCT event is only valid for reading/writing SCT registers.  Is anyone able to confirm this for me?

Would anyone be willing to recommend what SCT/DMA facilities I would use to accomplish this goal. 

Thanks in advance for your assistance.


.....lpc_guy469

[lpcware]

Content originally posted in LPCWare by mc on Tue Apr 29 17:42:00 MST 2014
Hi lpc_guy469,
The GPIO to SRAM transfer can be triggered by SCT. On a particular input or match you can generate a event. Based on this event SCT can start  transfer. You can use peripheral to memory mode. See the example at

http://www.lpcware.com/content/nxpfile/an11365-sct-camera-interface-design-lpc1800-and-lpc4300