imported>Wandell at 04:57, 7 June 2011

2011-06-07T04:57:08Z

← Older revision		Revision as of 04:57, 7 June 2011
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	/*		/*
	* CNI_trigger sketch for Arduino.		* CNI_trigger sketch for Arduino.
	*		*

imported>Wandell: Created page with "/* * CNI_trigger sketch for Arduino. * * * A simple sketch to generate TTl pulses when told to do so through a serial * port command. * * When running this sketch on a..."

2011-06-07T04:56:42Z

Created page with "/* * CNI_trigger sketch for Arduino. * * * A simple sketch to generate TTl pulses when told to do so through a serial * port command. * * When running this sketch on a..."

New page

/*
* CNI_trigger sketch for Arduino.
*
*
* A simple sketch to generate TTl pulses when told to do so through a serial
* port command.
*
* When running this sketch on a Teensy, be sure to set the "USB Type" to
* "Serial" (under the Arduino Tools menu).
*
* This sketch will also listen for input pulses and send out a serial port
* character whenever one is detected. It uses an external interrupt, so it
* can reliably detect very brief pulses. We use this to detect the GE 3.3v
* scope trigger pulses (~4 usec pulse duration).
*
*/

#include <Flash.h>
#include <Messenger.h>

#define BAUD 57600

#define DEFAULT_OUT_PULSE_MSEC 5
#define DEFAULT_IN_PULSE_STATE 0

// The approximate duration of the output pulse, in milliseconds.
// Note that we don't account for delays in the code, so it will
// always be a bit longer than this.
unsigned int g_outPulseDuration = DEFAULT_OUT_PULSE_MSEC;

// The input pin should be the pin mapped to INT0, unless you change
// the interrupt number below. The output pin can be any digital pin.
// Teensy2.0 has LED on pin 11 and INT0 on pin 5 (D0)
#define INTERRUPT 0
const byte g_outPin = 11;
const byte g_inPin = 5;

byte g_inPulseEdge = FALLING;

volatile byte g_outPinOn = false;
volatile unsigned long g_outPulseStart;

// Instantiate Messenger object used for serial port communication.
Messenger g_message = Messenger(',','[',']');

// Create the Message callback function. This function is called whenever a complete
// message is received on the serial port.
void messageReady() {
int val[10];
byte i = 0;
if(g_message.available()) {
// get the command byte
char command = g_message.readChar();
switch(command) {

case '?': // display help text
Serial << F("CNI Trigger Device\n");
Serial << F("Sends TTL pulses out on pin ") << (int)g_outPin << F(".\n");
Serial << F("Listens for pulses in on pin ") << (int)g_inPin << F(".\n");
Serial << F("\nCommands:\n");
Serial << F("[t] will send a trigger pulse. This also disables the input pulse\n");
Serial << F(" detection. Send a [p] command to re-enable it.\n\n");
Serial << F("[o,N] set the output pulse duration to N milliseconds. Send with\n");
Serial << F(" no argument to show the current pulse duration.\n\n");
Serial << F("[p] enable input pulse detection. Send a [t] to disable.\n\n");
Serial << F("[r] reset default state.\n\n");
break;

case 'o': // Set out-pulse duration (msec)
while(g_message.available()) val[i++] = g_message.readInt();
if(i>1){
Serial << F("ERROR: Set output pulse duration requires no more than one param.\n");
}else if(i==1){
g_outPulseDuration = val[0];
}
Serial << F("Output pulse duration is set to ") << g_outPulseDuration << F(" msec.\n");
break;

case 't': // force output trigger
// First force the pin low, in case it was already on. This will ensure that
// we get a change on the pin no matter what state we were in.
if(g_outPinOn) digitalWrite(g_outPin, LOW);
triggerOut();
// Automatically disable input pulse detection
setInPulseState(0);
break;

case 'p': // turn on input pulse detection
//Serial << F("Enabling input pulses\n");
setInPulseState(1);
break;

case 'r': // reset
setInPulseState(DEFAULT_IN_PULSE_STATE);
g_outPulseDuration = DEFAULT_OUT_PULSE_MSEC;
digitalWrite(g_outPin, LOW);
break;

default:
Serial << F("[") << command << F("]\n");
Serial << F("ERROR: Unknown command.\n\n");
} // end switch
} // end while
}

void setup(){
Serial.begin(BAUD);
Serial << F("*********************************************************\n");
Serial << F("* CNI Trigger firmware version ") << VERSION << F("\n");
Serial << F("* Copyright 2011 Bob Dougherty <bobd@stanford.edu>\n");
Serial << F("* http://cniweb.stanford.edu/wiki/CNI_widgets\n");
Serial << F("*********************************************************\n\n");

pinMode(g_inPin, INPUT);
pinMode(g_outPin, OUTPUT);
digitalWrite(g_outPin, LOW);
setInPulseState(DEFAULT_IN_PULSE_STATE);

// Attach the callback function to the Messenger
g_message.attach(messageReady);

Serial << F("CNI Trigger Ready. Send the ? command ([?]) for help.\n\n");
}

void loop(){
// Reset the output, if needed:
if(g_outPinOn){
// Turn off the output pin after the requested duration.
// Detect and correct counter wrap-around:
if(millis()<g_outPulseStart) g_outPulseStart += 4294967295UL;
if(millis()-g_outPulseStart > g_outPulseDuration)
digitalWrite(g_outPin, LOW);
}
// Handle Messenger's callback:
if(Serial.available()) g_message.process(Serial.read());
}

void setInPulseState(byte state){
// Turn on the internal pull-up resistor if we want to detect falling edges.
if(g_inPulseEdge==FALLING)
digitalWrite(g_inPin, HIGH);
else
digitalWrite(g_inPin, LOW);
// Attach or detach the interrupt
if(state)
attachInterrupt(INTERRUPT, triggerIn, g_inPulseEdge);
else
detachInterrupt(INTERRUPT);
}

// The following is an interrupt routine that is run each time the
// a pulse is detected on the trigger input pin.
void triggerIn(){
Serial << F("p");
}

void triggerOut(){
digitalWrite(g_outPin, HIGH);
g_outPinOn = true;
g_outPulseStart = millis();
}

CNI trigger code for serial port - Revision history

imported>Wandell at 04:57, 7 June 2011

imported>Wandell: Created page with "/* * CNI_trigger sketch for Arduino. * * * A simple sketch to generate TTl pulses when told to do so through a serial * port command. * * When running this sketch on a..."