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Rob Dobson / Mbed 2 deprecated TestAnalogWithSnippet

main.cpp@0:f75c555dc52b, 2010-01-05 (annotated)

Committer:: Bobty
Date:: Tue Jan 05 10:46:48 2010 +0000
Revision:: 0:f75c555dc52b

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User	Revision	Line number	New contents of line
Bobty	0:f75c555dc52b	1	// analog input p20 (ADC0[5], pin 3) test with stats
Bobty	0:f75c555dc52b	2
Bobty	0:f75c555dc52b	3	#include "mbed.h"
Bobty	0:f75c555dc52b	4
Bobty	0:f75c555dc52b	5	// Code from Simon Ford 2010-01-04
Bobty	0:f75c555dc52b	6	void mbedAdcInit()
Bobty	0:f75c555dc52b	7	{
Bobty	0:f75c555dc52b	8	// power on, clk divider /4
Bobty	0:f75c555dc52b	9	LPC_SC->PCONP \|= (1 << 12);
Bobty	0:f75c555dc52b	10	LPC_SC->PCLKSEL0 &= ~(0x3 << 24);
Bobty	0:f75c555dc52b	11
Bobty	0:f75c555dc52b	12	// software-controlled ADC settings
Bobty	0:f75c555dc52b	13	LPC_ADC->ADCR = (0 << 0) // SEL: 0 = no channels selected
Bobty	0:f75c555dc52b	14	\| (200 << 8) // CLKDIV: PCLK max ~= 25MHz, /25 to give safe 1MHz
Bobty	0:f75c555dc52b	15	\| (0 << 16) // BURST: 0 = software control
Bobty	0:f75c555dc52b	16	\| (0 << 17) // CLKS: not applicable
Bobty	0:f75c555dc52b	17	\| (1 << 21) // PDN: 1 = operational
Bobty	0:f75c555dc52b	18	\| (0 << 24) // START: 0 = no start
Bobty	0:f75c555dc52b	19	\| (0 << 27); // EDGE: not applicable
Bobty	0:f75c555dc52b	20
Bobty	0:f75c555dc52b	21	// setup P1_31 as sel 3 (ADC), mode 2 (no pull)
Bobty	0:f75c555dc52b	22	LPC_PINCON->PINSEL3 &= ~((unsigned int)0x3 << 30);
Bobty	0:f75c555dc52b	23	LPC_PINCON->PINSEL3 \|= (unsigned int)0x3 << 30;
Bobty	0:f75c555dc52b	24
Bobty	0:f75c555dc52b	25	LPC_PINCON->PINMODE3 &= ~((unsigned int)0x3 << 30);
Bobty	0:f75c555dc52b	26	LPC_PINCON->PINMODE3 \|= (unsigned int)0x2 << 30;
Bobty	0:f75c555dc52b	27
Bobty	0:f75c555dc52b	28	}
Bobty	0:f75c555dc52b	29
Bobty	0:f75c555dc52b	30	unsigned int mbedGetVal()
Bobty	0:f75c555dc52b	31	{
Bobty	0:f75c555dc52b	32	// Select channel and start conversion
Bobty	0:f75c555dc52b	33	LPC_ADC->ADCR &= ~0xFF;
Bobty	0:f75c555dc52b	34	LPC_ADC->ADCR \|= 1 << 5; // ADC0[5]
Bobty	0:f75c555dc52b	35	LPC_ADC->ADCR \|= 1 << 24;
Bobty	0:f75c555dc52b	36
Bobty	0:f75c555dc52b	37	// Repeatedly get the sample data until DONE bit
Bobty	0:f75c555dc52b	38	unsigned int data;
Bobty	0:f75c555dc52b	39	do {
Bobty	0:f75c555dc52b	40	data = LPC_ADC->ADGDR;
Bobty	0:f75c555dc52b	41	} while ((data & ((unsigned int)1 << 31)) == 0);
Bobty	0:f75c555dc52b	42	data = LPC_ADC->ADGDR;
Bobty	0:f75c555dc52b	43
Bobty	0:f75c555dc52b	44	// Stop conversion
Bobty	0:f75c555dc52b	45	LPC_ADC->ADCR &= ~(1 << 24);
Bobty	0:f75c555dc52b	46
Bobty	0:f75c555dc52b	47	return data;
Bobty	0:f75c555dc52b	48	}
Bobty	0:f75c555dc52b	49
Bobty	0:f75c555dc52b	50	// Code gleaned from MBED forum
Bobty	0:f75c555dc52b	51	void DispInfo()
Bobty	0:f75c555dc52b	52	{
Bobty	0:f75c555dc52b	53	printf("SystemCoreClock = %d Hz\n", SystemCoreClock);
Bobty	0:f75c555dc52b	54
Bobty	0:f75c555dc52b	55	int Fin = 12000000; // 12MHz XTAL
Bobty	0:f75c555dc52b	56
Bobty	0:f75c555dc52b	57	printf("PLL Registers:\n");
Bobty	0:f75c555dc52b	58	printf(" - PLL0CFG = 0x%08X\n", LPC_SC->PLL0CFG);
Bobty	0:f75c555dc52b	59	printf(" - CLKCFG = 0x%08X\n", LPC_SC->CCLKCFG);
Bobty	0:f75c555dc52b	60
Bobty	0:f75c555dc52b	61	int M = (LPC_SC->PLL0CFG & 0xFFFF) + 1;
Bobty	0:f75c555dc52b	62	int N = (LPC_SC->PLL0CFG >> 16) + 1;
Bobty	0:f75c555dc52b	63	int CCLKDIV = LPC_SC->CCLKCFG + 1;
Bobty	0:f75c555dc52b	64
Bobty	0:f75c555dc52b	65	printf("Clock Variables:\n");
Bobty	0:f75c555dc52b	66	printf(" - Fin = %d\n", Fin);
Bobty	0:f75c555dc52b	67	printf(" - M = %d\n", M);
Bobty	0:f75c555dc52b	68	printf(" - N = %d\n", N);
Bobty	0:f75c555dc52b	69	printf(" - CCLKDIV = %d\n", CCLKDIV);
Bobty	0:f75c555dc52b	70
Bobty	0:f75c555dc52b	71	int Fcco = (2 * M * 12000000) / N;
Bobty	0:f75c555dc52b	72	int CCLK = Fcco / CCLKDIV;
Bobty	0:f75c555dc52b	73
Bobty	0:f75c555dc52b	74	printf("Clock Results:\n");
Bobty	0:f75c555dc52b	75	printf(" - Fcco = %d\n", Fcco);
Bobty	0:f75c555dc52b	76	printf(" - CCLK = %d\n", CCLK);
Bobty	0:f75c555dc52b	77
Bobty	0:f75c555dc52b	78	printf("PCLKSEL0 = 0x%08x\n", LPC_SC->PCLKSEL0);
Bobty	0:f75c555dc52b	79	printf("PCLKSEL1 = 0x%08x\n", LPC_SC->PCLKSEL1);
Bobty	0:f75c555dc52b	80
Bobty	0:f75c555dc52b	81	}
Bobty	0:f75c555dc52b	82
Bobty	0:f75c555dc52b	83	int main() {
Bobty	0:f75c555dc52b	84
Bobty	0:f75c555dc52b	85	const int NUM_LOOPS = 100;
Bobty	0:f75c555dc52b	86	const int NUM_SAMPS = 1024;
Bobty	0:f75c555dc52b	87
Bobty	0:f75c555dc52b	88	mbedAdcInit();
Bobty	0:f75c555dc52b	89	wait_ms(100);
Bobty	0:f75c555dc52b	90
Bobty	0:f75c555dc52b	91	DispInfo();
Bobty	0:f75c555dc52b	92
Bobty	0:f75c555dc52b	93	// Table of deviation counts
Bobty	0:f75c555dc52b	94	const int DEV_HIST_SIZE = 10;
Bobty	0:f75c555dc52b	95	int devTable[DEV_HIST_SIZE+1];
Bobty	0:f75c555dc52b	96	for (int i = 0; i < DEV_HIST_SIZE+1; i++)
Bobty	0:f75c555dc52b	97	devTable[i] = 0;
Bobty	0:f75c555dc52b	98
Bobty	0:f75c555dc52b	99	// Run many times
Bobty	0:f75c555dc52b	100	double mean;
Bobty	0:f75c555dc52b	101	double lowestStdDev = 1024;
Bobty	0:f75c555dc52b	102	double highestStdDev = 0;
Bobty	0:f75c555dc52b	103	double sumForMean = 0;
Bobty	0:f75c555dc52b	104	for (int j = 0; j < NUM_LOOPS; j++)
Bobty	0:f75c555dc52b	105	{
Bobty	0:f75c555dc52b	106	// Get ADC readings
Bobty	0:f75c555dc52b	107	unsigned int adgdrVals[NUM_SAMPS];
Bobty	0:f75c555dc52b	108	unsigned int samples[NUM_SAMPS];
Bobty	0:f75c555dc52b	109	for(int i=0; i<NUM_SAMPS; i++) {
Bobty	0:f75c555dc52b	110	adgdrVals[i] = mbedGetVal();
Bobty	0:f75c555dc52b	111	samples[i] = (adgdrVals[i] >> 5) & 0x3ff;
Bobty	0:f75c555dc52b	112	wait_ms(1);
Bobty	0:f75c555dc52b	113	}
Bobty	0:f75c555dc52b	114
Bobty	0:f75c555dc52b	115	// Calculate mean
Bobty	0:f75c555dc52b	116	double localSum = 0;
Bobty	0:f75c555dc52b	117	for(int i=0; i<NUM_SAMPS; i++)
Bobty	0:f75c555dc52b	118	localSum += samples[i];
Bobty	0:f75c555dc52b	119	double localMean = localSum / NUM_SAMPS;
Bobty	0:f75c555dc52b	120	sumForMean += localSum;
Bobty	0:f75c555dc52b	121
Bobty	0:f75c555dc52b	122	// Calculate std-dev sum
Bobty	0:f75c555dc52b	123	double sumSqrDiffs = 0;
Bobty	0:f75c555dc52b	124	for(int i=0; i<NUM_SAMPS; i++)
Bobty	0:f75c555dc52b	125	sumSqrDiffs += (samples[i] - localMean) * (samples[i] - localMean);
Bobty	0:f75c555dc52b	126
Bobty	0:f75c555dc52b	127	// Calculate stdDev and see if low/high
Bobty	0:f75c555dc52b	128	double stdDev = sqrt(sumSqrDiffs / NUM_SAMPS);
Bobty	0:f75c555dc52b	129	if (lowestStdDev > stdDev)
Bobty	0:f75c555dc52b	130	lowestStdDev = stdDev;
Bobty	0:f75c555dc52b	131	if (highestStdDev < stdDev)
Bobty	0:f75c555dc52b	132	highestStdDev = stdDev;
Bobty	0:f75c555dc52b	133
Bobty	0:f75c555dc52b	134	// Histogram of values
Bobty	0:f75c555dc52b	135	for (int i = 0; i < NUM_SAMPS; i++)
Bobty	0:f75c555dc52b	136	{
Bobty	0:f75c555dc52b	137	int outOfBoundsDist = int(fabs(samples[i] - localMean));
Bobty	0:f75c555dc52b	138	if (outOfBoundsDist >= DEV_HIST_SIZE)
Bobty	0:f75c555dc52b	139	devTable[DEV_HIST_SIZE]++;
Bobty	0:f75c555dc52b	140	else
Bobty	0:f75c555dc52b	141	devTable[outOfBoundsDist]++;
Bobty	0:f75c555dc52b	142	}
Bobty	0:f75c555dc52b	143
Bobty	0:f75c555dc52b	144	// Show results that are out of bounds
Bobty	0:f75c555dc52b	145	printf("Results out of bounds for pass %d:\n", j);
Bobty	0:f75c555dc52b	146	for(int i=0; i<NUM_SAMPS; i++) {
Bobty	0:f75c555dc52b	147	if (fabs(samples[i] - localMean) > 5)
Bobty	0:f75c555dc52b	148	printf("%5d, 0x%04X, %d\n", i, adgdrVals[i], samples[i]);
Bobty	0:f75c555dc52b	149	}
Bobty	0:f75c555dc52b	150	}
Bobty	0:f75c555dc52b	151
Bobty	0:f75c555dc52b	152	// Show overall stats
Bobty	0:f75c555dc52b	153	mean = sumForMean / NUM_SAMPS / NUM_LOOPS;
Bobty	0:f75c555dc52b	154	printf("Mean: %.2f\n", mean);
Bobty	0:f75c555dc52b	155	printf("Std-dev (highest, lowest): %.2f, %.2f\n", highestStdDev, lowestStdDev);
Bobty	0:f75c555dc52b	156	printf("Deviation Table\n");
Bobty	0:f75c555dc52b	157	printf("Dist.\tCount\n");
Bobty	0:f75c555dc52b	158	for (int i = 0; i < DEV_HIST_SIZE+1; i++)
Bobty	0:f75c555dc52b	159	printf("%s%d\t%d\n", i == DEV_HIST_SIZE ? "> " : "", i, devTable[i]);
Bobty	0:f75c555dc52b	160	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	05 Jan 2010
Imports:	1
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	1

main.cpp@0:f75c555dc52b, 2010-01-05 (annotated)

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