Test
example2.h
- Committer:
- ktseng
- Date:
- 2019-04-25
- Revision:
- 18:e7d62a489a83
- Parent:
- 12:1dfee7208043
File content as of revision 18:e7d62a489a83:
/* * 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"); }