Revision 0:337ad0fe7734, committed 2013-12-29

Comitter:

Mischa

Date:

Sun Dec 29 01:00:30 2013 +0000

Commit message:

First version.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DMAFuncGen.cpp	Sun Dec 29 01:00:30 2013 +0000
@@ -0,0 +1,120 @@
+#include "assert.h"
+#include "DMAFuncGen.h"
+
+//DigitalOut led1(LED1);
+
+DMAFuncGen::DMAFuncGen(MODDMA& dma, MODDMA::CHANNELS channel) : dma(dma) {
+    conf.channelNum( channel );
+    buffer_size = 0;
+    buffer = NULL;
+}
+
+#define DAC_POWER_MODE  (0 << 16)  // DAC output power mode.
+
+uint16_t DMAFuncGen::operator[](const uint16_t idx) {
+    assert(buffer!=NULL);
+    assert(idx<buffer_size);
+    return buffer[idx] & 0xFFC0;
+}
+
+void DMAFuncGen::set(int idx, uint16_t x) {
+    // V = (x>>6) × ((VrefP - VrefN)/1024) + VrefN; VrefN = 0V; VrefP = 3.3V;
+    buffer[idx] = DAC_POWER_MODE | (x & 0xFFC0);
+}
+
+void DMAFuncGen::Connect() {
+    // Connect DAC to pin
+    LPC_PINCON->PINSEL1 &= ~(3UL <<20);
+    LPC_PINCON->PINSEL1 |= 2UL <<20; //AOUT
+    LPC_PINCON->PINMODE1 &= ~(3UL <<20);
+    LPC_PINCON->PINMODE1 |= (2UL <<20);  // neither pull-up nor pull-down
+    LPC_PINCON->PINMODE_OD0 &= ~(1UL <<26);  // normal (not open drain) mode
+}
+ 
+void DMAFuncGen::Disconnect() {
+    LPC_PINCON->PINSEL1 &= ~(3UL <<20);
+    LPC_PINCON->PINSEL1 |= 1UL <<20; //AD0.3, input
+    LPC_PINCON->PINMODE1 &= ~(3UL <<20);
+    LPC_PINCON->PINMODE1 |= (2UL <<20);  // neither pull-up nor pull-down
+    LPC_PINCON->PINMODE_OD0 &= ~(1UL <<26);  // normal (not open drain) mode
+}
+
+void DMAFuncGen::Setup(void) {
+    // Prepare the GPDMA system.
+    lli.srcAddr( (uint32_t) buffer );
+    lli.dstAddr( (uint32_t) &LPC_DAC->DACR );
+    lli.nextLLI( (uint32_t) &lli);
+    lli.control( dma.CxControl_TransferSize(buffer_size)
+               | dma.CxControl_SBSize((uint32_t)MODDMA::_1) 
+               | dma.CxControl_DBSize((uint32_t)MODDMA::_1) 
+               | dma.CxControl_SWidth((uint32_t)MODDMA::word) 
+               | dma.CxControl_DWidth((uint32_t)MODDMA::word) 
+               | dma.CxControl_SI() 
+               | dma.CxControl_I() );
+
+    conf.srcMemAddr  ( (uint32_t) buffer )
+      ->dstMemAddr   ( MODDMA::DAC )  // unnecessary?
+      ->transferSize ( buffer_size )
+      ->transferType ( MODDMA::m2p )
+      ->dstConn      ( MODDMA::DAC )
+      ->dmaLLI       ( (uint32_t) &lli )
+      ->attach_tc    ( this, &DMAFuncGen::TC_callback ) 
+      ->attach_err   ( this, &DMAFuncGen::ERR_callback );
+
+    // Setup dma.
+    if (!dma.Setup( &conf )) {
+        error("Unexpected error during DMA.Setup(conf)");
+    }
+}        
+
+float DMAFuncGen::Frequency() {
+    float f;
+    f=SystemCoreClock;
+    const int divisors[4] = {4,1,2,8};
+    f/=divisors[((LPC_SC->PCLKSEL0) >> 22) & 0x03];
+    f/=buffer_size;
+    f/=LPC_DAC->DACCNTVAL;
+    return f;
+}
+
+void DMAFuncGen::SetFrequency(float f) {
+    // Set the transfer frequency.
+    float cntval;
+    cntval = SystemCoreClock/(f*buffer_size);
+    const int PCLK_DAC[4] = {1,2,0,3}; 
+    int i=0;
+    int divisor=1;
+    while (((cntval/divisor)>65535) && (i<4)) {divisor*=2; i++; }
+    if (i==4) { divisor=8; i=3; }
+    LPC_SC->PCLKSEL0 &= ~(3UL<<22);
+    LPC_SC->PCLKSEL0 |=  ((uint32_t) PCLK_DAC[i])<<22;
+    LPC_DAC->DACCNTVAL = cntval/divisor;
+}
+
+void DMAFuncGen::Start() {
+    dma.Enable( &conf );
+    
+    // Enable DMA, and TC interrupt
+    LPC_DAC->DACCTRL = 3UL<<2; // DMA_ENA set, DMA_CNT set
+}
+
+void DMAFuncGen::Stop() {
+    dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS) conf.channelNum() );
+    LPC_DAC->DACCTRL = 0UL<<2;
+}
+
+// Configuration callback on TC
+void DMAFuncGen::TC_callback(void) {
+    
+    // Just show sending buffer complete.
+    // led1 = !led1; 
+
+    // Clear DMA IRQ flags.
+    if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq(); 
+}
+
+// Configuration callback on Error
+void DMAFuncGen::ERR_callback(void) {
+    error("Unexpected error - DMA error callback.");
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DMAFuncGen.h	Sun Dec 29 01:00:30 2013 +0000
@@ -0,0 +1,63 @@
+#ifndef MBED_DMAFUNCGEN_H
+#define MBED_DMAFUNCGEN_H
+
+#include "mbed.h"
+#include "MODDMA.h"
+
+//! DMAFuncGen class generates a waveform on Analog output using Direct Memory Access alone.
+class DMAFuncGen {
+public:
+    /// Create DMAFucGen instance
+    /// @param dma The dma to use.
+    /// @param channel The dma channel to use for transferring data to the D/A converter.
+    DMAFuncGen(MODDMA& dma, MODDMA::CHANNELS channel);
+
+    /// Number of data points in the waveform. Must be set by client.
+    int buffer_size;
+    /// Buffer for the binary data that will be transferred by DMA. Must be allocated by client.
+    uint32_t* buffer;
+
+    /// Set waveform value for a specified data point.
+    /// @param idx The index of the data point in #buffer, must be in range 0..#buffer_size-1.
+    /// @param x The value for the D/A, in the range 0..65535.
+    void set(int idx, uint16_t x);
+    /// Get waveform value for a specified data point
+    /// @param idx The index of the data point in the #buffer, in the range 0..#buffer_size-1.
+    /// @returns The value for the data point, in the range 0..65535.
+    uint16_t operator[](const uint16_t idx);
+    
+    /// Connect the D/A converter pin (enable output)
+    void Connect();
+    /// Disconnect the D/A converter pin (pin becomes tri-state)
+    void Disconnect();
+
+    /// Reference to the DMA instance   
+    MODDMA& dma;
+    
+    /// Set up the dma.
+    /// Must set #buffer and #buffer_size first.
+    void Setup(void);
+    
+    /// Set waveform frequency
+    /// @note Must set #buffer_size first.
+    /// @param f Frequency of a complete cycle of the waveform (in Hz). 
+    void SetFrequency(float f);
+    /// Read the actual waveform frequency that will be generated.
+    float Frequency();
+    
+    /// Start generating the waveform (start dma)
+    void Start();
+    /// Stop generating the waveform (but waits for the current cycle to complete)
+    void Stop();
+
+private:
+    MODDMA_Config conf;
+    MODDMA_LLI lli;
+
+    /// ISR routine, called on Terminal Count
+    void TC_callback(void);
+    /// ISR routine, called on dma ERRor
+    void ERR_callback(void);
+};
+
+#endif