Jacob Isakson
jisakson3
Diff: SignalGenDAC.cpp
- Revision:
- 0:c1a4c1e9618c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SignalGenDAC.cpp Mon Dec 05 02:01:53 2022 +0000
@@ -0,0 +1,200 @@
+//
+// Signal Generate DAC Driver
+//
+// Derived from AN10917: Memory to DAC data transfers using the LPC1700's DMA
+//
+
+#include "SignalGenDAC.h"
+
+#define PI 3.14159 // for the sine-wave
+
+/// The linked list structure used to control the DMA transfer
+///
+typedef struct {
+ uint32_t source; /// start of source area
+ uint32_t destination;/// start of destination area
+ uint32_t next; /// address of next strLLI in chain
+ uint32_t control; /// DMACCxControl register
+} LinkListItem_t;
+
+/// The DACsignal memory, which is DMA sent to the DAC to play the waveform,
+/// produced by scaling the VoltSignal array
+///
+float VoltSignal[SIGNAL_MEM_ENTRIES] __attribute__ ((section("AHBSRAM0")));
+signed long DACsignal[SIGNAL_MEM_ENTRIES] __attribute__ ((section("AHBSRAM0")));
+
+/// The linked list item record, used by the DMA engine to decide how to play
+///
+LinkListItem_t llio __attribute__ ((section("AHBSRAM0")));
+
+
+SignalGenDAC::SignalGenDAC(PinName _aout, float _minV, float _maxV) :
+ minV(_minV), maxV(_maxV) {
+ aout = new AnalogOut(_aout);
+}
+
+SignalGenDAC::~SignalGenDAC() {
+}
+
+void SignalGenDAC::Start(bool oneShot) {
+ printf("Start(%d) w/%d samples\r\n", oneShot ? 1 : 0, numSamples);
+ isOn = (oneShot) ? false : true;
+
+ llio.source = (uint32_t)DACsignal;
+ llio.destination = (uint32_t)&LPC_DAC->DACR;
+ llio.next = (uint32_t)&llio;
+ llio.control = (1<<26) | (2<<21) | (2<<18) | numSamples;
+
+ LPC_SC->PCONP |= (1<<29);
+
+ /* Enable GPDMA and sync logic */
+ LPC_GPDMA->DMACConfig = 1;
+ LPC_GPDMA->DMACSync = (1<<6);
+
+ /* Load DMA Channel0 */
+ LPC_GPDMACH0->DMACCSrcAddr = (uint32_t)DACsignal;
+ LPC_GPDMACH0->DMACCDestAddr = (uint32_t)&LPC_DAC->DACR;
+ LPC_GPDMACH0->DMACCLLI = (oneShot) ? 0 : (uint32_t)&llio;
+
+ int playSampleCount = numSamples + oneShot;
+ LPC_GPDMACH0->DMACCControl = playSampleCount // transfer size (0 - 11) = 64
+ | (0 << 12) // source burst size (12 - 14) = 1
+ | (0 << 15) // destination burst size (15 - 17) = 1
+ | (2 << 18) // source width (18 - 20) = 32 bit
+ | (2 << 21) // destination width (21 - 23) = 32 bit
+ | (0 << 24) // source AHB select (24) = AHB 0
+ | (0 << 25) // destination AHB select (25) = AHB 0
+ | (1 << 26) // source increment (26) = increment
+ | (0 << 27) // destination increment (27) = no increment
+ | (0 << 28) // mode select (28) = access in user mode
+ | (0 << 29) // (29) = access not bufferable
+ | (0 << 30) // (30) = access not cacheable
+ | (0 << 31); // terminal count interrupt disabled
+
+ LPC_GPDMACH0->DMACCConfig = 1
+ | (0 << 1) // source peripheral (1 - 5) = none
+ | (7 << 6) // destination peripheral (6 - 10) = DAC
+ | (1 << 11) // flow control (11 - 13) = mem to per
+ | (0 << 14) // (14) = mask out error interrupt
+ | (0 << 15) // (15) = mask out terminal count interrupt
+ | (0 << 16) // (16) = no locked transfers
+ | (0 << 18); // (27) = no HALT
+
+ /* DACclk = 25 MHz, so 10 usec interval */
+ LPC_DAC->DACCNTVAL = 18; // 16-bit reload value
+ /* DMA, timer running, dbuff */
+ LPC_DAC->DACCTRL =
+ 1<<3 // DMA_ENA dma burst is enabled
+ | 1<<2 // CNT_ENA Timeout couner is enabled
+ | 1<<1; // DBLBUF_ENA double-buffering enabled
+}
+
+void SignalGenDAC::Stop(void) {
+ printf("Stop()\r\n");
+ LPC_GPDMACH0->DMACCLLI = 0;
+ while (LPC_GPDMACH0->DMACCConfig & 1)
+ wait_ms(1);
+ aout->write(offset / maxV);
+ isOn = false;
+}
+
+
+void SignalGenDAC::PrepareWaveform(SG_Waveform mode, float _frequency, float _dutycycle, float _voltage, float _offset) {
+ int x, dcCount, firstQtr, lastQtr;
+ frequency = _frequency;
+ dutycycle = _dutycycle;
+ voltage = _voltage;
+ offset = _offset;
+ float upp = rangelimit(offset + voltage/2, minV, maxV);
+ float mid = rangelimit(offset, minV, maxV);
+ float low = rangelimit(offset - voltage/2, minV, maxV);
+ float v;
+ numSamples = 128; // Ideally, compute this based on the frequency for good resolution
+ dcCount = dutycycle/100.0 * numSamples;
+ firstQtr = dcCount / 2;
+ lastQtr = dcCount + (numSamples - dcCount)/2;
+
+ // Set the timebased based on the frequency
+ if (isOn) {
+ Stop();
+ }
+ printf("Generate wave for mode: %d\r\n", mode);
+ switch (mode) {
+ case SG_SINE:
+ for (x=0; x<numSamples; x++) {
+ if (x < dcCount) {
+ v = offset + voltage/2 * sin(x * 1 * PI / dcCount);
+ } else {
+ v = offset - voltage/2 * sin((x - dcCount) * 1 * PI / (numSamples-dcCount));
+ }
+ v = rangelimit(v, minV, maxV);
+ VoltSignal[x] = v;
+ }
+ VoltSignal[numSamples] = rangelimit(offset, minV, maxV);
+ break;
+ case SG_SQUARE:
+ for (x=0; x<numSamples; x++) {
+ if (0 && x == 0) {
+ v = rangelimit(offset, minV, maxV);
+ } else if (x < dcCount) {
+ v = rangelimit(offset + voltage/2, minV, maxV);
+ } else {
+ v = rangelimit(offset - voltage/2, minV, maxV);
+ }
+ VoltSignal[x] = v;
+ }
+ VoltSignal[numSamples] = rangelimit(offset, minV, maxV);
+ break;
+ case SG_TRIANGLE:
+ for (x=0; x<numSamples; x++) {
+ if (x < firstQtr) {
+ v = voltage/2 * (float)x/(firstQtr);
+ v += offset;
+ } else if (x < dcCount) {
+ v = voltage/2 * (float)x/(firstQtr);
+ v = voltage - (v - offset);
+ } else if (x < lastQtr) {
+ v = voltage * (float)(x - dcCount)/(numSamples - dcCount);
+ v = offset - v;
+ } else {
+ v = voltage * (float)(x - dcCount)/(numSamples - dcCount);
+ v = v + offset - voltage;
+ }
+ VoltSignal[x] = v;
+ }
+ VoltSignal[numSamples] = rangelimit(offset, minV, maxV);
+ break;
+ case SG_SAWTOOTH:
+ for (x=0; x<numSamples; x++) {
+ if (x < dcCount) {
+ v = offset - voltage/2 + (float)x/dcCount * voltage/2;
+ } else {
+ v = offset + (float)(x - dcCount)/(numSamples - dcCount) * voltage/2;
+ }
+ v = rangelimit(v, minV, maxV);
+ VoltSignal[x] = v;
+ }
+ VoltSignal[numSamples] = rangelimit(offset, minV, maxV);
+ break;
+ case SG_USER:
+ break;
+ }
+ //printf("DAC Data %3.2f %3.2f\r\n", voltage, offset);
+ for (x=0; x<=numSamples; x++) {
+ DACsignal[x] = ((uint16_t)(VoltSignal[x]/maxV * 1023) << 6);
+ printf("%3d, %5.3f, %d\r\n", x, VoltSignal[x], DACsignal[x]);
+ }
+ if (!isOn) {
+ aout->write(offset / maxV);
+ }
+}
+
+float SignalGenDAC::rangelimit(float value, float min, float max) {
+ if (value < min)
+ return min;
+ else if (value > max)
+ return max;
+ else
+ return value;
+}
+