zoom/pc/read.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <getopt.h>
#include <stdint.h>
#include <string.h>
#include <syslog.h>
#include <err.h>
#include <linux/serial.h>
#include "serial-util.h"

int hex = 0;
int dec = 0;
int screen = 0;
int unprocessed = 0;
int total = 0;

int process(const uint8_t *buf, int len);

int main(int argc, char *argv[])
{
	char *device=strdup("/dev/ttyUSB0");
	int rate=500000;
	int fd;
	int getopt_index;
	char buf[1024];
	int len;

	static struct option long_opts[] = {
		{ "device", required_argument, NULL, 'd' },
		{ "rate", required_argument, NULL, 'r' },
		{ "hex", no_argument, NULL, 'x' },
		{ "dec", no_argument, NULL, 'D' },
		{ "total", no_argument, NULL, 't' },
		{ "raw", no_argument, NULL, 'R' },
		{ "unprocessed", no_argument, NULL, 'u' },
		{ "screen", no_argument, NULL, 's' },
		{ "help", no_argument, NULL, 'h' },
		{ 0, 0, 0, 0 }
	};
	int help=0;
	char c;

	while ((c = getopt_long(argc, argv, "d:r:xDutsh?",
				long_opts, &getopt_index)) != -1) {
		switch(c) 
		{
		case 'd':
			free(device);
			device = strdup(optarg);
			break;
		case 'r':
			rate = atoi(optarg);
			if(rate == 0)
				errx(1, "invalid rate: %s",optarg);
			break;
		case 'x':
			hex = 1;
			break;
		case 'D':
			dec = 1;
			break;
		case 't':
			total = 1;
			break;
		case 'u':
			unprocessed = 1;
			break;
		case 's':
			screen = 1;
			break;
		case 'h':
		case '?':
		default:
			help = 1;
			break;
		}
	}
	
	if (help) {
		fprintf(stderr, "Zoom Nilm Client\n");
		fprintf(stderr, "usage: %s [options]\n\n", *argv);
		fprintf(stderr, "  -d,  --device %-14s serial port\n", device);
		fprintf(stderr, "  -r,  --rate %-16d baud rate\n", rate);
		fprintf(stderr, "  -x,  --hex                   hex out\n");
		fprintf(stderr, "  -u,  --unprocessed           dump raw unprocessed data\n");
		fprintf(stderr, "  -s,  --screen                send \\r instead of \\n\n");
		fprintf(stderr, "  -t,  --total                 just display total amps\n");
		fprintf(stderr, "  -h,  --help                  this cruft\n");
		return 1;
	}

	if ((fd = serial_open(device, rate)) == -1)
		errx(1, "serial_open failed");

	len = 0;
	while (1) {
		int processed, n;
		n = read(fd, buf + len, sizeof(buf) - len);
		if (n <= 0) 
			err(1, "read");
		len += n;
		processed = process((uint8_t *) buf, len);
		memmove(buf, buf + processed, len - processed);
		len -= processed;
	}
	
	return 1;
}

uint16_t current_to_dac(float amps)
{
	float tmp;
	uint16_t dacc;

	tmp = 536.0 / 1.0 * amps + 32524;
	if (tmp < 0)
		tmp = 0;
	if (tmp > 65535)
		tmp = 65535;
	dacc = (uint16_t)(tmp + 0.5);

	return dacc;
}

/* Convert the DAC output value to an effective current in the measuring loop */
float dac_to_current(uint16_t dacv)
{
	float amps;
	amps = ((float)dacv - 32524.0) * 1.0 / 536.0;
	return amps;
}

float adc12_to_current(int16_t picv)
{
	float amps;

	if (picv < 0)
		picv = 0;
	if (picv > 2047)
		picv = 2047;
	
	amps = (picv - 1024.0) / 404.0;
	return amps;
}

int process(const uint8_t *buf, int len)
{
	int n = 0;
	uint16_t dac, tmp;
	int16_t adc;
	float idac = dac_to_current(dac);
	float iadc = adc12_to_current(adc);

	if (unprocessed) {
		n = write(fileno(stdout), buf, len);
		if (n >= 0)
			return n;
		return 0;
	}

	/* Process blocks */
 retry:
	for (; (n + 4) <= len; buf += 4, n += 4) {
		if ((!buf[0] & 0x80) ||
		    (buf[1] & 0x80) ||
		    (buf[2] & 0x80) ||
		    (buf[3] & 0x80)) {
			/* badly formed data, eat one byte and retry */
			buf++;
			n++;
			goto retry;
		}

		tmp = ((buf[0] & 0x7f) << 5) |
			((buf[1] & 0x7c) >> 2);
		dac = ((buf[1] & 0x03) << 14) |
			(buf[2] << 7) | buf[3];
		
		/* sign-extend ADC value */
		if (tmp & 0x0800) 
			tmp |= 0xF000;
		else
			tmp &= ~0xF000;
		adc = (int16_t)tmp;

		/* compute floating-point currents */
		idac = dac_to_current(dac);
		iadc = adc12_to_current(adc);

		/* send it out */
		if (hex) {
			printf("%04x %03x", dac, adc & 0x0FFF);
		} else if (dec) {
			printf("%d %d", dac, adc & 0x0FFF);
		} else if (total) {
			printf("%.6f", idac - iadc);
		} else {
			printf("DAC: %5d (% f)  ADC: % 5d (% f)  Total: % 10.6f amps",
			       dac, idac, (int16_t)adc, iadc, idac - iadc);

			if (adc < 0 || adc >= 2047)
				printf("   **** adc limit");
		}

		if (screen) 
			printf("\033[K\r");
		else
			printf("\n");
	}
	return n;
}