Primitive ADC + DMA testing and benchmarking on the Maple r5

main.cpp

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <math.h>

#include "wirish.h"
#include "dma.h"

// Force init to be called *first*, i.e. before static object allocation.
// Otherwise, statically allocated objects that need libmaple may fail.
__attribute__((constructor)) void premain() { init(); }

#define DMA_DEV DMA1
#define DMA_CHANNEL DMA_CH1

#define BUF_TO_PRINT 8
#define BUF_SIZE 512
uint16_t adcDMABuffer[BUF_SIZE];

uint16_t printPeriod = 100;
uint32_t lastPrinted = 0;
uint32_t currentMillis = 0;
uint32_t startedMillis = 0;

int main()
{

	for(int i = 0; i < BUF_SIZE; i++) adcDMABuffer[i] = 0;

	// Setup DMA
	dma_init(DMA_DEV);
	dma_setup_transfer(DMA_DEV, DMA_CHANNEL,
						&ADC1->regs->DR, DMA_SIZE_16BITS,
						adcDMABuffer,    DMA_SIZE_16BITS,
						(DMA_MINC_MODE | DMA_CIRC_MODE | DMA_TRNS_CMPLT)
						);
	dma_set_num_transfers(DMA_DEV, DMA_CHANNEL, BUF_SIZE);

	int isDMAEnabled = 0;
	
	while(isDMAEnabled == 0)
	{
		currentMillis = millis();
		
		// Wait 6 seconds before starting DMA.
		if(currentMillis >= 6000)
		{
			startedMillis = currentMillis;
			
			isDMAEnabled = 1;
		
			// Configure ADC and Enable DMA
			adc_init(ADC1);
			adc_set_sample_rate(ADC1, ADC_SMPR_7_5); // Sample rate?
			adc_set_exttrig(ADC1, 1); // Does something useful, I think?
			adc_set_reg_seqlen(ADC1, 1); // 1 Channel per sequence?
			ADC1->regs->SQR3 = 1; // Channel 1
			// DMA, Enable, SW Start, Cont. Mode, SWSTART Ext. Sel
			ADC1->regs->CR2 |= (ADC_CR2_DMA | ADC_CR2_ADON | ADC_CR2_SWSTART | ADC_CR2_CONT | ADC_CR2_EXTSEL);
			dma_enable(DMA1, DMA_CHANNEL);	
			
			SerialUSB.println("DMA Channel Enabled!");
		}
		else
		{
			if(currentMillis > (lastPrinted + printPeriod))
			{
				lastPrinted = currentMillis;
				SerialUSB.print("[");
				SerialUSB.print(currentMillis);
				SerialUSB.println("] Warming Up...");
			}
		}
	}
	
	uint8_t previousISRBits = 0;
	uint16_t isrCounts = 0;

	while(1)
	{	
		currentMillis = millis();

		uint8_t isr_bits = dma_get_isr_bits(DMA_DEV, DMA_CHANNEL);

		if(currentMillis > (lastPrinted + printPeriod))
		{
			lastPrinted = currentMillis;
			
			dma_channel_reg_map *ch_regs = dma_channel_regs(DMA_DEV, DMA_CHANNEL);

			SerialUSB.print("[");
			SerialUSB.print(currentMillis - startedMillis);
			SerialUSB.print("] ISR bits: 0x");
			SerialUSB.print((int32)isr_bits, HEX);
	
			SerialUSB.print(" CCR: 0x");
			SerialUSB.print((int64)ch_regs->CCR, HEX);
	
			SerialUSB.print(" CNDTR: ");		
			SerialUSB.print((int64)ch_regs->CNDTR);
			
			SerialUSB.print(" ISR Counts: ");		
			SerialUSB.print(isrCounts);
	
			SerialUSB.print(" Buffer contents: ");
			for (int i = 0; i < (BUF_SIZE <= BUF_TO_PRINT ? BUF_SIZE : BUF_TO_PRINT); i++)
			{
				SerialUSB.print('\'');
				SerialUSB.print(adcDMABuffer[i]);
				SerialUSB.print('\'');
				if (i < BUF_SIZE - 1) SerialUSB.print(", ");
			}
			if(BUF_SIZE > BUF_TO_PRINT) SerialUSB.print("...");
	
			SerialUSB.println();
		}
		
		if(isr_bits == 0x7)
		{
			//SerialUSB.println("** Clearing ISR bits.");
			dma_clear_isr_bits(DMA_DEV, DMA_CHANNEL);
		}
		
		if(previousISRBits != isr_bits && isr_bits == 0x7)
		{
			isrCounts++;
		}
		
		previousISRBits = isr_bits;

	}	
    
    return 0;
}