dac_sinewave.c

优龙LPC1788开发板资料

/*****
 * @file		dac_sinewave_test.c
 * @purpose		This example describes how to use DAC to generate a sine wave
 * 			  	using DMA to transfer data
 * @version		2.0
 * @date
 * @author		NXP MCU SW Application Team
 *---------------------------------------------------------------------
 * Software that is described herein is for illustrative purposes only
 * which provides customers with programming information regarding the
 * products. This software is supplied "AS IS" without any warranties.
 * NXP Semiconductors assumes no responsibility or liability for the
 * use of the software, conveys no license or title under any patent,
 * copyright, or mask work right to the product. NXP Semiconductors
 * reserves the right to make changes in the software without
 * notification. NXP Semiconductors also make no representation or
 * warranty that such application will be suitable for the specified
 * use without further testing or modification.
 **********************************************************************/
#include "lpc177x_8x_dac.h"
#include "lpc177x_8x_gpdma.h"
#include "lpc177x_8x_clkpwr.h"

/* Example group ----------------------------------------------------------- */
/** @defgroup DAC_SineWave	SineWave
 * @ingroup DAC_Examples
 * @{
 */

#define _ONE_POSITIVE_HALF		(0)
#define _DMA_USING				(0)


/************************** PRIVATE MACROS *************************/
#define SINEWAVE_AMPLITUDE			512

//Thi minimum value is as amplitude to make all the signed not to be less than 0 (zero)
#define SINEWAVE_OFFSET				SINEWAVE_AMPLITUDE

#if _ONE_POSITIVE_HALF
#define NUM_SINE_SAMPLE	30
#define SINE_FREQ_IN_HZ	100
#else
#define NUM_SINE_SAMPLE	60
#define SINE_FREQ_IN_HZ	60
#endif

/** DMA size of transfer */
#define DMA_SIZE		NUM_SINE_SAMPLE

/************************** PRIVATE VARIABLES *************************/
GPDMA_Channel_CFG_Type GPDMACfg;

/*-------------------------MAIN FUNCTION------------------------------*/
/*********************************************************************//**
 * @brief		c_entry: Main DAC program body
 * @param[in]	None
 * @return 		int
 **********************************************************************/
void DAC_SineWave(void)
{
	DAC_CONVERTER_CFG_Type DAC_ConverterConfigStruct;
	GPDMA_LLI_Type DMA_LLI_Struct;

	uint32_t dac_sine_lut[NUM_SINE_SAMPLE];
	uint32_t cnt,count;

	uint32_t sin_0_to_90_16_samples[16]={\
										0,		1045,	2079,	3090,
										4067,	5000,	5877,	6691,
										7431,	8090,	8660,	9135,
										9510,	9781,	9945,	10000\
										};

	// Clear all value
	for(cnt = 0; cnt < NUM_SINE_SAMPLE; cnt++)
	{
		dac_sine_lut[cnt] = 0;
	}

	//Prepare DAC sine look up table
	for(cnt = 0; cnt < NUM_SINE_SAMPLE; cnt++)
	{
		if(cnt <= 15)
		{
			dac_sine_lut[cnt] = SINEWAVE_OFFSET + (SINEWAVE_AMPLITUDE * sin_0_to_90_16_samples[cnt]) / 10000;
		}
		else if(cnt <= 30)
		{
			dac_sine_lut[cnt] =  SINEWAVE_OFFSET + (SINEWAVE_AMPLITUDE * sin_0_to_90_16_samples[30-cnt]) / 10000;
		}
		else if(cnt <= 45)
		{
			dac_sine_lut[cnt] = SINEWAVE_OFFSET - (SINEWAVE_AMPLITUDE * sin_0_to_90_16_samples[cnt-30]) / 10000;
		}
		else
		{
			dac_sine_lut[cnt] = SINEWAVE_OFFSET - (SINEWAVE_AMPLITUDE * sin_0_to_90_16_samples[60-cnt]) / 10000;
		}

		//To make sure the output value is not over 10-bit width of DAC
		if(dac_sine_lut[cnt] > 0x3FF)
			dac_sine_lut[cnt] = 0x3FF;

#if _DMA_USING
		//Shift the value before DMA to DAC component in case of using DMA
		dac_sine_lut[cnt] = (dac_sine_lut[cnt] << 6);
#endif
	}

#if _DMA_USING
	//Prepare DMA link list item structure
	DMA_LLI_Struct.SrcAddr= (uint32_t)dac_sine_lut;

	DMA_LLI_Struct.DstAddr= (uint32_t)&(LPC_DAC->CR);

	DMA_LLI_Struct.NextLLI= (uint32_t)&DMA_LLI_Struct;

	DMA_LLI_Struct.Control= DMA_SIZE
								| (2<<18) //source width 32 bit
								| (2<<21) //dest. width 32 bit
								| (1<<26); //source increment

	/* GPDMA block section -------------------------------------------- */
	/* Initialize GPDMA controller */
	GPDMA_Init();

	// Setup GPDMA channel --------------------------------
	// channel 0
	GPDMACfg.ChannelNum = 0;

	// Source memory
	GPDMACfg.SrcMemAddr = (uint32_t)(dac_sine_lut);

	// Destination memory - unused
	GPDMACfg.DstMemAddr = 0;

	// Transfer size
	GPDMACfg.TransferSize = DMA_SIZE;

	// Transfer width - unused
	GPDMACfg.TransferWidth = 0;

	// Transfer type
	GPDMACfg.TransferType = GPDMA_TRANSFERTYPE_M2P;

	// Source connection - unused
	GPDMACfg.SrcConn = 0;

	// Destination connection
	GPDMACfg.DstConn = GPDMA_CONN_DAC;

	// Linker List Item - unused
	GPDMACfg.DMALLI = (uint32_t)&DMA_LLI_Struct;

	// Setup channel with given parameter
	GPDMA_Setup(&GPDMACfg);
#endif

	DAC_ConverterConfigStruct.CNT_ENA = SET;
	DAC_ConverterConfigStruct.DMA_ENA = RESET;

	DAC_Init(0);

	cnt = CLKPWR_GetCLK(CLKPWR_CLKTYPE_PER);

	// set time out for DAC
	// clk = sine_freq * number_of_samples_per_sine_cycle * sample_freq 	(pulses of clock)
	// => sample_freq = clk / (sine_freq * number_of_samples_per_sine_cycle)

	cnt = cnt/(SINE_FREQ_IN_HZ * NUM_SINE_SAMPLE * 5);

	DAC_SetDMATimeOut(0, cnt);

#if _DMA_USING
	DAC_ConverterConfigStruct.CNT_ENA = SET;
	DAC_ConverterConfigStruct.DMA_ENA = SET;
#endif
	DAC_ConfigDAConverterControl(0, &DAC_ConverterConfigStruct);

#if _DMA_USING
	// Enable GPDMA channel 0
	GPDMA_ChannelCmd(0, ENABLE);
#else
	cnt = 0;
	count = 0;

	while(count++ <= 30000)
	{
		DAC_UpdateValue(0, dac_sine_lut[cnt]);

		while(!DAC_IsIntRequested(0));

		cnt ++;
		if(cnt == NUM_SINE_SAMPLE)
			cnt = 0;
	}
#endif
}

void DAC_SineWave_Dis(void){

#if _DMA_USING
	// Disable GPDMA channel 0
	GPDMA_ChannelCmd(0, DISABLE);
#endif

}
/*
 * @}
*/