Jared Baxter / Mbed 2 deprecated Impedance_Fast_Circuitry_print_V_I

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Dependencies:   mbed-dsp mbed

Fork of Impedance_Fast_Circuitry by Jared Baxter

Diff: dma.cpp

Revision:
35:df40c4566826
Parent:
34:44cc9b76a507
Child:
36:07d8a3143967
--- a/dma.cpp	Sun Jan 25 02:45:58 2015 +0000
+++ b/dma.cpp	Sun Jan 25 06:32:11 2015 +0000
@@ -14,7 +14,7 @@
  * @adc_reads = the length of buffer and the number of reads the DMA completes
  * */
  
-void dma_init(uint16_t* buffer,int adc_reads)
+void dma_init(uint16_t* buffer,int len)
 {
     // Enable clock for DMAMUX and DMA
     SIM_SCGC6 |= SIM_SCGC6_DMAMUX_MASK;
@@ -41,12 +41,13 @@
     DMA_TCD0_NBYTES_MLNO = 0x02;
         
     // Current major iteration count (a single iteration of 5 bytes)
-    DMA_TCD0_CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(adc_reads);
-    DMA_TCD0_BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(adc_reads);
+    DMA_TCD0_CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(len);
+    DMA_TCD0_BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(len);
     
     // Adjustment value used to restore the source and destiny address to the initial value
+    // After reading 'len' number of times, the DMA goes back to the beginning by subtracting len*2 from the address (going back to the address of 'buffer')
     DMA_TCD0_SLAST = 0x00;      // Source address adjustment
-    DMA_TCD0_DLASTSGA = -0x10;  // Destination address adjustment
+    DMA_TCD0_DLASTSGA = -(len*2);  // Destination address adjustment
     
     // Setup control and status register
     DMA_TCD0_CSR = 0;