dma.c

00001 /*
00002  * dma.c
00003  *
00004  *  Created on: 03/07/2011
00005  *      Author: francisco
00006  */
00007 #include <LPC17xx.h>
00008 #include "dma.h"
00009 
00010 #define LPC_GPDMACH          ((LPC_GPDMACH_TypeDef   **) LPC_GPDMACH0_BASE )
00011 
00012 void init_dma()
00013 {
00014     LPC_SC->PCONP |= 1<<29;     //Power GPDMA module
00015 
00016     LPC_GPDMA->DMACConfig = 1;  //Enable GPDMA
00017 
00018     //Clear any previous interrupts
00019     LPC_GPDMA->DMACIntTCClear = 0xFF;
00020     LPC_GPDMA->DMACIntErrClr = 0xFF;
00021 
00022     NVIC_SetPriority(DMA_IRQn,(1<<__NVIC_PRIO_BITS) - 1);
00023     NVIC_EnableIRQ(DMA_IRQn);
00024 }
00025 
00026 void setup_channel(dmaLinkedListNode* pList,int ch,int src,int dst)
00027 {
00028     //Initialize the channel with previously configured LL;
00029     LPC_GPDMACH0->DMACCSrcAddr = pList->sourceAddr;
00030     LPC_GPDMACH0->DMACCDestAddr = pList->destAddr;
00031     LPC_GPDMACH0->DMACCControl = pList->dmaControl;
00032     LPC_GPDMACH0->DMACCLLI = (unsigned long int) pList & 0xFFFFFFFC; //Lower bits must be 0
00033 
00034     int transfer_type;
00035     if(src == DMA_MEMORY && dst != DMA_MEMORY)
00036     {
00037         transfer_type = DMA_MEMORY_TO_PERIPHERAL;
00038         src = 0;
00039     }
00040     else if(src != DMA_MEMORY && dst == DMA_MEMORY)
00041     {
00042         transfer_type = DMA_PERIPHERAL_TO_MEMORY;
00043         dst = 0;
00044     }
00045     else if(src == DMA_MEMORY && dst == DMA_MEMORY)
00046     {
00047         transfer_type = DMA_MEMORY_TO_MEMORY;
00048         src=dst = 0;
00049     }
00050     else if(src != DMA_MEMORY && dst != DMA_MEMORY)
00051         transfer_type = DMA_PERIPHERAL_TO_PERIPHERAL;
00052 
00053     //Set up all relevant bits
00054     LPC_GPDMACH0->DMACCConfig = (src<<1) | (dst<<5) | (transfer_type<<11) | (1<<15);
00055 
00056     //Finally, enable the channel -
00057     LPC_GPDMACH0->DMACCConfig |= 1<<0;
00058 }
00059 
00060 void stop_channel()
00061 {
00062     LPC_GPDMACH0->DMACCConfig &= ~(1<<0);
00063 }