http://http://diytec.web.fc2.com/mark2r2/
Dependencies: EthernetNetIf NTPClient_NetServices mbed ConfigFile
Diff: MODDMA/example2.h
- Revision:
- 0:08a4d61cd84c
diff -r 000000000000 -r 08a4d61cd84c MODDMA/example2.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MODDMA/example2.h Tue Sep 20 12:46:26 2011 +0000 @@ -0,0 +1,138 @@ +/* + * 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.baud(460800); + 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"); +} +