overte-lubosz/SerialInterface.cpp
Philip Rosedale cabcbbc0d2 Latest work
2012-11-02 16:49:08 -07:00

105 lines
3 KiB
C++

//
// SerialInterface.cpp
//
// Used to read Arduino/Maple ADC data from an external device using a serial port (over USB)
//
#include "SerialInterface.h"
#include <iostream>
// These includes are for serial port reading/writing
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
int serial_fd;
const int MAX_BUFFER = 100;
char serial_buffer[MAX_BUFFER];
int serial_buffer_pos = 0;
// For accessing the serial port
int init_port(int baud)
{
serial_fd = open(SERIAL_PORT_NAME, O_RDWR | O_NOCTTY | O_NDELAY);
if (serial_fd == -1) return -1; // Failed to open port
struct termios options;
tcgetattr(serial_fd,&options);
switch(baud)
{
case 9600: cfsetispeed(&options,B9600);
cfsetospeed(&options,B9600);
break;
case 19200: cfsetispeed(&options,B19200);
cfsetospeed(&options,B19200);
break;
case 38400: cfsetispeed(&options,B38400);
cfsetospeed(&options,B38400);
break;
case 115200: cfsetispeed(&options,B115200);
cfsetospeed(&options,B115200);
break;
default:cfsetispeed(&options,B9600);
cfsetospeed(&options,B9600);
break;
}
options.c_cflag |= (CLOCAL | CREAD);
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
tcsetattr(serial_fd,TCSANOW,&options);
return 0; // Success!
}
int read_sensors(int first_measurement, float * avg_adc_channels, int * adc_channels)
{
int samples_read = 0;
const float AVG_RATE = 0.001; // 0.00001;
char bufchar[1];
while (read(serial_fd, bufchar, 1) > 0)
{
serial_buffer[serial_buffer_pos] = bufchar[0];
serial_buffer_pos++;
// Have we reached end of a line of input?
if ((bufchar[0] == '\n') || (serial_buffer_pos >= MAX_BUFFER))
{
samples_read++;
// At end - Extract value from string to variables
if (serial_buffer[0] != 'p')
{
sscanf(serial_buffer, "%d %d %d %d %d %d %d %d", /* Needs to match Num Channels */
&adc_channels[0],
&adc_channels[1],
&adc_channels[2],
&adc_channels[3],
&adc_channels[4],
&adc_channels[5],
&adc_channels[6],
&adc_channels[7]);
for (int i = 0; i < NUM_CHANNELS; i++)
{
if (!first_measurement)
avg_adc_channels[i] = (1.f - AVG_RATE)*avg_adc_channels[i] +
AVG_RATE*(float)adc_channels[i];
else
{
avg_adc_channels[i] = (float)adc_channels[i];
}
}
}
// Clear rest of string for printing onscreen
while(serial_buffer_pos++ < MAX_BUFFER) serial_buffer[serial_buffer_pos] = ' ';
serial_buffer_pos = 0;
}
}
return samples_read;
}