File content as of revision 18:2aa6ffab5522:

/*
 * This example was provided to support Mbed forum thread:-
 * http://mbed.org/forum/mbed/topic/1798
 */
 
#include "mbed.h"
#include "MODDMA.h"

#define SAMPLE_BUFFER_LENGTH 32

DigitalOut led1(LED1);
DigitalOut led2(LED2);

MODDMA dma;
Serial pc(USBTX, USBRX);

// ISR set's this when transfer complete.
bool dmaTransferComplete = false;

// Function prototypes for IRQ callbacks.
// See definitions following main() below.
void TC0_callback(void);
void ERR0_callback(void);

int main() {

    // Create a buffer to hold the ADC samples and clear it.
    // Note, we are going to sample two ADC inputs so they
    // end up in this buffer "interleaved". So you will want
    // a buffer twice this size to a real life given sample
    // frequency. See the printf() output for details.
    uint32_t adcInputBuffer[SAMPLE_BUFFER_LENGTH];    
    memset(adcInputBuffer, 0, sizeof(adcInputBuffer));
    
    // We use the ADC irq to trigger DMA and the manual says
    // that in this case the NVIC for ADC must be disabled.
    NVIC_DisableIRQ(ADC_IRQn);
    
    // Power up the ADC and set PCLK
    LPC_SC->PCONP    |=  (1UL << 12);
    LPC_SC->PCLKSEL0 &= ~(3UL << 24); // PCLK = CCLK/4 96M/4 = 24MHz
    
    // Enable the ADC, 12MHz,  ADC0.0 & .1
    LPC_ADC->ADCR  = (1UL << 21) | (1UL << 8) | (3UL << 0); 
    
    // Set the pin functions to ADC
    LPC_PINCON->PINSEL1 &= ~(3UL << 14);  /* P0.23, Mbed p15. */
    LPC_PINCON->PINSEL1 |=  (1UL << 14);
    LPC_PINCON->PINSEL1 &= ~(3UL << 16);  /* P0.24, Mbed p16. */
    LPC_PINCON->PINSEL1 |=  (1UL << 16);
    
    // Setup the serial port to print out results.
    pc.baud(115200);
    pc.printf("ADC with DMA example\n");
    pc.printf("====================\n");
    
    // Prepare an ADC configuration.
    MODDMA_Config *conf = new MODDMA_Config;
    conf
     ->channelNum    ( MODDMA::Channel_0 )
     ->srcMemAddr    ( 0 )
     ->dstMemAddr    ( (uint32_t)adcInputBuffer )
     ->transferSize  ( SAMPLE_BUFFER_LENGTH )
     ->transferType  ( MODDMA::p2m )
     ->transferWidth ( MODDMA::word )
     ->srcConn       ( MODDMA::ADC )
     ->dstConn       ( 0 )
     ->dmaLLI        ( 0 )
     ->attach_tc     ( &TC0_callback )
     ->attach_err    ( &ERR0_callback )
    ; // end conf.
    
    // Prepare configuration.
    dma.Setup( conf );
    
    // Enable configuration.
    dma.Enable( conf );
    
    // Enable ADC irq flag (to DMA).
    // Note, don't set the individual flags,
    // just set the global flag.
    LPC_ADC->ADINTEN = 0x100;

    // Enable burst mode on inputs 0 and 1.
    LPC_ADC->ADCR |= (1UL << 16); 
    
    while (1) {
        // When transfer complete do this block.
        if (dmaTransferComplete) {
            delete conf; // No memory leaks, delete the configuration.
            dmaTransferComplete = false;
            for (int i = 0; i < SAMPLE_BUFFER_LENGTH; i++) {
                int channel = (adcInputBuffer[i] >> 24) & 0x7;
                int iVal = (adcInputBuffer[i] >> 4) & 0xFFF;
                double fVal = 3.3 * (double)((double)iVal) / ((double)0x1000); // scale to 0v to 3.3v
                pc.printf("Array index %02d : ADC input channel %d = 0x%03x %01.3f volts\n", i, channel, iVal, fVal);                  
            }
        }
        
        // Just flash LED1 for something to do.
        led1 = !led1;
        wait(0.25);        
    }
}

// Configuration callback on TC
void TC0_callback(void) {
    
    MODDMA_Config *config = dma.getConfig();
    
    // Disbale burst mode and switch off the IRQ flag.
    LPC_ADC->ADCR &= ~(1UL << 16);
    LPC_ADC->ADINTEN = 0;    
    
    // Finish the DMA cycle by shutting down the channel.
    dma.haltAndWaitChannelComplete( (MODDMA::CHANNELS)config->channelNum());
    dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
    
    // Tell main() while(1) loop to print the results.
    dmaTransferComplete = true;            
    
    // Switch on LED2 to show transfer complete.
    led2 = 1;        
    
    // Clear DMA IRQ flags.
    if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq();    
    if (dma.irqType() == MODDMA::ErrIrq) dma.clearErrIrq();
}

// Configuration callback on Error
void ERR0_callback(void) {
    // Switch off burst conversions.
    LPC_ADC->ADCR |= ~(1UL << 16);
    LPC_ADC->ADINTEN = 0;
    error("Oh no! My Mbed EXPLODED! :( Only kidding, go find the problem");
}