Need help with direct port manipulation for time critical application

Projects Programming
1

I have an arduino uno project which flashes LEDs to music beats and standart DigitalWrite is just not fast enough. I was told to either use DigitalWriteFast library or use direct port manipulation which is pretty much the fastest way of controlling LEDS.

So, can I manipulate my 13 LEDs as follows? I was reading up on the official arduino tutorial and this is what I understood from it. Basically, at one point in code, I need to start to toggle all 13 LEDs on and off. I will keep it simple for the sake of understanding. I would use other pins than 0 and 1, but they are all occupied.

so,

DDRD = B11111111; // sets Arduino pins 0-7 as outputs
DDRB = DDRB | B111101; // sets Arduino pins 8-13 as outputs, without changing the value of pin 9

PORTD = B11111111; // sets digital pins 0-7 HIGH
PORTB = B111101; // set 8-13 HIGH, without changing the value of pin 9.

PORTD = B00000000; // sets digital pins 0-7 LOW
PORTB = B000000; // how do you make 8-13 LOW again, without changing the value of pin 9??

I need to toggle all the pins simultaneously. on and off.

What is the proper way of writing all 13 pins high and low at the same time, while skipping pin 9?

Cheers.

2

if you are having problems with time critical operations have you considered using an Arduino Due or a Raspberry Pi ?

3

What is the proper way of writing all 13 pins high and low at the same time,

On an eight bit-wide port, there is no "proper way".
You need to redefine your concept of "simultaneously", from the point-of-view view of a processor executing 16000 instruction cycles per millisecond.

If you need to exclude one pin, then you need to use simple mask operations.

4

Simple mask operations...

Set all low except pin 9 use AND

PORTD &= B00000000;
PORTB &= B00000010;

Set all high except pin 9 use OR

PORTD |= B11111111;
PORTB |= B11111101;

Reverse all pins except pin 9 use XOR (high pins go low and low pins go high)

PORTD^=B11111111;
PORTB^=B11111101;

5

wzaggle:
Simple mask operations...

Set all low except pin 9 use AND

PORTD &= B00000000;
PORTB &= B00000010;

Set all high except pin 9 use OR

PORTD |= B11111111;
PORTB |= B11111101;

Reverse all pins except pin 9 use XOR (high pins go low and low pins go high)

PORTD^=B11111111;
PORTB^=B11111101;

I'm a little bit confused now. But that is not your fault. Can you please make it even more simple for me.

All I want is to do the following:

Here turn all LEDS (except pin9) on

Here turn all LEDS(except pin9) off.

Cheers.

6

How can you be confused?
Why didn't you try the code in reply #3?

7

AWOL:
How can you be confused?
Why didn't you try the code in reply #3?

I tried it. I get error messages.

Because the following examples are only for turning pins high or low. I need the "set output" bits also. Besides, in PORTB |= B11111101 doesn't make sense. It can only be up to 13 right? so, shouldn't it be PORTB |=B111101 instead?

Set all high except pin 9 use OR

PORTD |= B11111111;
PORTB |= B11111101;
8

AWOL:
How can you be confused?
Why didn't you try the code in reply #3?

Just managed to compile. The code works, but there is no difference in speed. So, the problem must be somewhere else.

9

arduinoware:
Just managed to compile. The code works, but there is no difference in speed. So, the problem must be somewhere else.

show a video of what's happening.

10

The code works, but there is no difference in speed.

Having seen the code in your other threads there is a lot going on between turning the LEDs on and off. Please post the relevant code here.

11

UKHeliBob:
Having seen the code in your other threads there is a lot going on between turning the LEDs on and off. Please post the relevant code here.

BulldogLowell:
show a video of what's happening.

Ok. I have recorded a video. will be posting shortly.

I thought, may be the other parts of the sketch could be interfering with the buzzing effect. So, I tried the stand alone version of the music only sketch, but the result was the same:

/*
  Arduino Mario Bros Tunes
  With Piezo Buzzer and PWM

  Connect the positive side of the Buzzer to pin 3,
  then the negative side to a 1k ohm resistor. Connect
  the other side of the 1 k ohm resistor to
  ground(GND) pin on the Arduino.

  by: Dipto Pratyaksa
  last updated: 31/3/13
*/

/*************************************************
   Public Constants
 *************************************************/

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978

#define melodyPin 9
//Mario main theme melody
int melody[] = {
  NOTE_E7, NOTE_E7, 0, NOTE_E7,
  0, NOTE_C7, NOTE_E7, 0,
  NOTE_G7, 0, 0,  0,
  NOTE_G6, 0, 0, 0,

  NOTE_C7, 0, 0, NOTE_G6,
  0, 0, NOTE_E6, 0,
  0, NOTE_A6, 0, NOTE_B6,
  0, NOTE_AS6, NOTE_A6, 0,

  NOTE_G6, NOTE_E7, NOTE_G7,
  NOTE_A7, 0, NOTE_F7, NOTE_G7,
  0, NOTE_E7, 0, NOTE_C7,
  NOTE_D7, NOTE_B6, 0, 0,

  NOTE_C7, 0, 0, NOTE_G6,
  0, 0, NOTE_E6, 0,
  0, NOTE_A6, 0, NOTE_B6,
  0, NOTE_AS6, NOTE_A6, 0,

  NOTE_G6, NOTE_E7, NOTE_G7,
  NOTE_A7, 0, NOTE_F7, NOTE_G7,
  0, NOTE_E7, 0, NOTE_C7,
  NOTE_D7, NOTE_B6, 0, 0
};
//Mario main them tempo
int tempo[] = {
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  9, 9, 9,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,

  9, 9, 9,
  12, 12, 12, 12,
  12, 12, 12, 12,
  12, 12, 12, 12,
};
//Underworld melody
int underworld_melody[] = {
  NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
  NOTE_AS3, NOTE_AS4, 0,
  0,
  NOTE_C4, NOTE_C5, NOTE_A3, NOTE_A4,
  NOTE_AS3, NOTE_AS4, 0,
  0,
  NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
  NOTE_DS3, NOTE_DS4, 0,
  0,
  NOTE_F3, NOTE_F4, NOTE_D3, NOTE_D4,
  NOTE_DS3, NOTE_DS4, 0,
  0, NOTE_DS4, NOTE_CS4, NOTE_D4,
  NOTE_CS4, NOTE_DS4,
  NOTE_DS4, NOTE_GS3,
  NOTE_G3, NOTE_CS4,
  NOTE_C4, NOTE_FS4, NOTE_F4, NOTE_E3, NOTE_AS4, NOTE_A4,
  NOTE_GS4, NOTE_DS4, NOTE_B3,
  NOTE_AS3, NOTE_A3, NOTE_GS3,
  0, 0, 0
};
//Underwolrd tempo
int underworld_tempo[] = {
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  3,
  12, 12, 12, 12,
  12, 12, 6,
  6, 18, 18, 18,
  6, 6,
  6, 6,
  6, 6,
  18, 18, 18, 18, 18, 18,
  10, 10, 10,
  10, 10, 10,
  3, 3, 3
};

void setup(void)
{
  DDRD = B11111111;
  DDRB = B111111;

}
void loop()
{
  //sing the tunes
  sing(1);
  sing(1);
  sing(2);
}
int song = 0;

void sing(int s) {
  // iterate over the notes of the melody:
  song = s;
  if (song == 2) {
    int size = sizeof(underworld_melody) / sizeof(int);
    for (int thisNote = 0; thisNote < size; thisNote++) {

      // to calculate the note duration, take one second
      // divided by the note type.
      //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
      int noteDuration = 1000 / underworld_tempo[thisNote];

      buzz(melodyPin, underworld_melody[thisNote], noteDuration);

      // to distinguish the notes, set a minimum time between them.
      // the note's duration + 30% seems to work well:
      int pauseBetweenNotes = noteDuration * 1.30;
      delay(pauseBetweenNotes);

      // stop the tone playing:
      buzz(melodyPin, 0, noteDuration);

    }

  } else {
    int size = sizeof(melody) / sizeof(int);
    for (int thisNote = 0; thisNote < size; thisNote++) {

      // to calculate the note duration, take one second
      // divided by the note type.
      //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
      int noteDuration = 1000 / tempo[thisNote];

      buzz(melodyPin, melody[thisNote], noteDuration);

      // to distinguish the notes, set a minimum time between them.
      // the note's duration + 30% seems to work well:
      int pauseBetweenNotes = noteDuration * 1.30;
      delay(pauseBetweenNotes);

      // stop the tone playing:
      buzz(melodyPin, 0, noteDuration);

    }
  }
}

void buzz(int targetPin, long frequency, long length) {
  PORTD |= B11111111;
  PORTB |= B111101;

  long delayValue = 1000000 / frequency / 2; // calculate the delay value between transitions
  //// 1 second's worth of microseconds, divided by the frequency, then split in half since
  //// there are two phases to each cycle
  long numCycles = frequency * length / 1000; // calculate the number of cycles for proper timing
  //// multiply frequency, which is really cycles per second, by the number of seconds to
  //// get the total number of cycles to produce
  for (long i = 0; i < numCycles; i++) { // for the calculated length of time...
    digitalWrite(targetPin, HIGH); // write the buzzer pin high to push out the diaphram
    delayMicroseconds(delayValue); // wait for the calculated delay value
    digitalWrite(targetPin, LOW); // write the buzzer pin low to pull back the diaphram
    delayMicroseconds(delayValue); // wait again or the calculated delay value
  }
  PORTD &= B00000000;
  PORTB &= B000010;
}
12

Here is the full version of the code attached.

Oh, by the way, I forgot to mention. I have not connected the LEDs directly. The LEDs are wired to collectors and emitters of 2N2222 transistors. Arduino output pins control the transistor bases. Could that be why?

Full_work_copy.ino (14.7 KB)

13 
int underworld_tempo[] = {
  12, 12, 12, 12,

Why are you wasting so much memory?

14

AWOL:

int underworld_tempo[] = {

12, 12, 12, 12,


Why are you wasting so much memory?

I have no idea what that even means. I did not write this code. Can you make it better?

15

arduinoware:
I have an arduino uno project which flashes LEDs to music beats and standart DigitalWrite is just not fast enough.

I doubt it.

16

aarg:
I doubt it.

And you are probably right. direct port manipulation made no difference. :slight_smile:

17

aarg:
I doubt it.

See reply #2

18

UKHeliBob:
Having seen the code in your other threads there is a lot going on between turning the LEDs on and off. Please post the relevant code here.

I have done a couple of tests with adjusting a few parameters in the code. But the issue (regardless of the changes) seems to be that between the beats of the buzzer, the LED output doesn't go to 0 it hovers at low voltage and sort of flickers. Can it have something to do with transistors that I'm using?

19

arduinoware:
Can it have something to do with transistors that I'm using?

You know the drill by now. Post a schematic.

20

arduinoware:
Can it have something to do with transistors that I'm using?

Why not replace your LED array / transistor setup with a single LED connected directly to the control pin? That should help you determine if your problem is hardware or software.