LabVIEW Interface for Arduino Discussions
arduino mega PWMing
Hello Nathan,
Thanks for your help..Please see attached files for clarification. Yes, I did use LIFA 2.2.0.79 and currently, I am using a demo version of LabVIEW 2012 to see if I can get somewhere with it.
Based on what I understand, At-Mega 2560 is using Timer/Counter for PWM signal generation. PWM pin5 = OC3A, PWM pin2 = OC3B, & PWM pin3 = OC3C. But PWM pin4 is = OC0B which belongs to a different Timer/Counter set and that's why on my scope capture it shows Ch-3 (the blue trace) is missed aligned with the rest. Please kindly correct me if I am completely out of the alignment here.
Basically, I am trying to generate 4 PWM signals to exercise my DUT as follow:
Ch-1: is for a clocking purpose
CH-2 - Ch-4 are to just control the programming current for a three channels buck regulator with a different pulse width and delay to just see how/if can I break the part.
Hello Sammy_K,
Thanks for stepping in. To be honest, I am not that good in programming, that's why I like LabVIEW. It's takes a huge amount of time out of my headache and allow me to get my job done and achieving my goal in timely manner.
Back to your questions, yes.. I do need to synchronize the channels so that can get my start time to abuse my DUT at a known state, but if there's an alternative option(s) that would allow me to do what I want to do, I am open for that. Please do advise..
On the Arduino IDE side, I have been trying to generate the waveforms that I hope to have and also trying to "SYNCH" the TIMER together from the document and the discussion that I found, I am not able to accomplish the synchronization at all. Maybe I am not doing something correctly and it's entirely possible. Below is what/how my script looklike:
#include <avr/interrupt.h>
#include <util/delay_basic.h>
//GTCCR = (1<<TSM)|(1<<PSRASY)|(1<<PSRSYNC); // halt all timers
unsigned long time;
void setup()
{
Serial.begin(9600);
GTCCR = (1<<TSM)|(1<<PSRASY)|(1<<PSRSYNC); // halt all timers
int outputPsuB = 12; // Timer1-B
int outputPsuC = 13; // Timer1-C
// PSU outputs via timer1
pinMode(outputPsuB, OUTPUT); // select Pin as ch-B
pinMode(outputPsuC, OUTPUT); // select Pin as ch-C
TCNT0 = 0; // set timer0 to 0
TCNT1H = 0; // set timer1 high byte to 0
TCNT1L = 0; // set timer1 low byte to 0
TCNT2 = 0; // set timer2 to 0
// set all timers to the same value
GTCCR = 0; // release all timers
// GTCCR = (1<<TSM)|(1<<PSRASY)|(1<<PSRSYNC); // halt all timers
// GTCCR = B10000000; // Turning "ON" TSM: Timer/Counter Synchronization Mode
TCCR1A = B00101001; // Phase and frequency correct PWM change at OCRA
TCCR1B = B10011; // System clock / 1024 from prescaler
OCR1A = 7000; // 0.78125 Hz
OCR1B = 1000; // 75% PWM
OCR1C = 2000; // 5% PWM
// TCCR0A = TCCR0A & 0x3F; // disable OC0A from timer0
}
void loop()
{
Serial.print("Time: ");
time = millis();
//prints time since program started
Serial.println(time);
// wait a second so as not to send massive amounts of data
delay(0);
}
For a better explanation, I am attaching my waveforms sketch for your reference and thanks again for your response.
Hope to hear from you soon
Sy D.
Hello Nathan_B.,
Please accept my sincere apology for not being clear to you. If you are looking for an answer to what exactly the device that I am trying to test, there are some product proprietry on my DUT that I cannot share. The best I can tell you is what I am trying to achieve and it is what I can describe about the waveform that I have drawn and attached above:
a.) I am trying to generate 4 PWM signals to control my DUT.
b.) Signal-1 is a 50% duty cycle CLK from ~ 20Hz to 10KHz
c.) Signal-2, 3, & 4 are PWM signals that have the same frequency as the CLK but with an adjustable duty cycle of ~5% to 95% of the total period with programmable/controllable delay from when signal-1 beginning @ time zero.
The 4 signals that I am trying to generate are all output signals from the Arduino. I do not need to read anything back at all.
I hope this would make enough sense for you to relate to and hope you won't mind respond with some solution to help me out.
Sincerely,
Sy D.
