---

nees-adxl.c File Reference

Read from the Crossbow ADXL 2-axis accelerometer board and stream it. More...

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <pthread.h>
#include <getopt.h>
#include <sys/termios.h>
#include <fcntl.h>
#include "nsds_util.h"
#include "flog.h"
#include "adxl_util.h"

Go to the source code of this file.

Data Structures
struct	thread_params_t
	Struct passed to data thread - holds TCP port descriptor and serial port. More...
Functions
int	data_active_count (void)
	Return number of active channels.
bool	data_channel_enabled (const int channel_id)
	Is a channel subscribed?
int	data_channel_flag (const int channel_id, const bool subscribe)
	Mark a channel as subscribed or unsubscribed.
void *	daq_thread_main (void *arg)
	Data handling thread.
int	daq_do_work (const int control_socket, const int data_socket, const thread_params_t *thread_params)
	Main worker routine: read / parse / respond.
void	daq_main_loop (const int daq_port, const char *serial_portname, const int sample_delay)
	Open network socket, loop doing work until control-c.
int	main (int argc, char *argv[])
	Init the network, talk to all.
Variables
const int	DAQ_PORT = 55050
	Default TCP port to listen on.
bool	streaming_active
	Semaphore boolean.
const int	TCP_Q_LEN = 1
	Depth of TCP queue.
struct {
pthread_mutex_t   mutex
bool   active [NUM_ADXL_CHANNELS]
int   num_active
}	chan_struct
	Shared structure for subscribed data channels.

---

Detailed Description

Read from the Crossbow ADXL 2-axis accelerometer board and stream it.

Note:

Requires the flog messaging library, nsds_util lib as well

Based on fake_daq.c

Date:

4/30/03

Author:

Paul Hubbard

Definition in file nees-adxl.c.

---

Function Documentation

int daq_do_work (  const int  control_socket, const int  data_socket, const thread_params_t *  thread_params )

Main worker routine: read / parse / respond. Date: 9/5/02 Author: Paul Hubbard Return values: 0  OK, != 0 means error Parameters: control_socket  FD of control connection data_socket  FD of data connection thread_params  Bundle of params for data thread, passed through Read commands, respond as required. Starts data thread upon receiving the first data subscription, and closes it when no more channels are streaming. Definition at line 375 of file nees-adxl.c. References daq_thread_main(), data_active_count(), data_channel_flag(), NUM_ADXL_CHANNELS, and streaming_active. Referenced by daq_main_loop().

void daq_main_loop (  const int  daq_port, const char *  serial_portname, const int  sample_delay )

Open network socket, loop doing work until control-c. Date: 9/5/02 Note: Opens server socket This handles the dropped connections and other TCP errors, mostly by restarting the connects. Also kills data thread if connections die. Parameters: daq_port  TCP port number of main server socket serial_portname  ADXL serial port, passed to data thread sample_delay  If non-zero, inter-sample delay in microseconds Definition at line 624 of file nees-adxl.c. References control_break, daq_do_work(), thread_params_t::delay_usec, thread_params_t::serial_port, thread_params_t::socket_fd, streaming_active, and TCP_Q_LEN. Referenced by main().

void* daq_thread_main (  void *  arg  )

Data handling thread. Transient thread to send data out the data channel. Dead simple. Note: Opens and closes the ADXL at thread startup and shutdown based on fake_daq and nees-di Parameters: arg  Ptr to thread_params_t struct Return values: Null  always Definition at line 245 of file nees-adxl.c. References adxl_close(), ADXL_DATUM_LEN, adxl_open(), adxl_read(), control_break, data_active_count(), data_channel_enabled(), thread_params_t::delay_usec, adxl_reading_t::G, NUM_ADXL_CHANNELS, thread_params_t::serial_port, thread_params_t::socket_fd, and streaming_active. Referenced by daq_do_work().

int data_active_count (  void   )

Return number of active channels. Return values: Number  active, <0 if error Note: Common with nees-di code, roll into library? Date: 9/27/02 Definition at line 74 of file nees-adxl.c. References chan_struct. Referenced by daq_do_work(), and daq_thread_main().

bool data_channel_enabled (  const int  channel_id  )

Is a channel subscribed? Locks mutex and checks array to see if a channel is subscribed. Parameters: channel_id  Channel ID to check Return values: True  or false, false if error Note: uses mutex lock on chan_struct Common with nees-di code, roll into library? Date: 9/24/02 Definition at line 112 of file nees-adxl.c. References chan_struct, and NUM_ADXL_CHANNELS. Referenced by daq_thread_main().

int data_channel_flag (  const int  channel_id, const bool  subscribe )

Mark a channel as subscribed or unsubscribed. Lock the mutex, set the bit, report if it changed. Note: Idempotent - call multiple times w/no harm done. Parameters: channel_id  Channel ID in question subscribe  if true, subscribe, if false un-sub Return values: 0  if OK, non-zero if error Note: Uses chan_struct and mutex therein Common with nees-di code, roll into library? Date: 9/24/02 Definition at line 159 of file nees-adxl.c. References chan_struct, and NUM_ADXL_CHANNELS. Referenced by daq_do_work().

int main (  int  argc, char *  argv[] )

Init the network, talk to all. Parse options, installs signal handler, calls worker routine. Note: Driver port passed on command line Ditto w/sample rate Parameters: argc  Argc as passed by shell argv  Argv as passed by shell Returns: 0 All is good Non-zero All is not good Definition at line 719 of file nees-adxl.c. References ADXL_MAX_RATE_HZ, adxl_sighandler(), control_break, daq_main_loop(), DAQ_PORT, and NUM_ADXL_CHANNELS.

---

Variable Documentation

bool active[NUM_ADXL_CHANNELS]

R/W mutex for struct. Definition at line 54 of file nees-adxl.c.

struct { ... } chan_struct

Shared structure for subscribed data channels. Referenced by data_active_count(), data_channel_enabled(), and data_channel_flag().

const int DAQ_PORT = 55050

Default TCP port to listen on. Definition at line 42 of file nees-adxl.c. Referenced by main().

pthread_mutex_t mutex

Definition at line 53 of file nees-adxl.c.

int num_active

Definition at line 55 of file nees-adxl.c.

bool streaming_active

Semaphore boolean. Definition at line 45 of file nees-adxl.c. Referenced by daq_do_work(), daq_main_loop(), and daq_thread_main().

const int TCP_Q_LEN = 1

Depth of TCP queue. Definition at line 48 of file nees-adxl.c. Referenced by daq_main_loop().

---