'test port command: generate 3 phase 50Hz

'defines
samples = 210 'tuner to achieve 20ms (50Hz)
' = 3 * Int(samples / 3) 'make 120 degrees 3 phase, multiple of 3
bits = 6
resol = 2^(bits-1)
Print "resolution = ";resol*2;"   using ";samples;" samples per loop"

'init
setport
setsine

'loop
Do 'Timer = 0
For i%=1 To samples
 Port(gp0,18) = a%(i%)
Next i%
Loop 'x=Timer
Print "loop time = ";x;" ms"
End

Sub setport
SetPin gp0,dout
SetPin gp1,dout
SetPin gp2,dout
SetPin gp3,dout
SetPin gp4,dout
SetPin gp5,dout
SetPin gp6,dout
SetPin gp7,dout
SetPin gp8,dout
SetPin gp9,dout
SetPin gp10,dout
SetPin gp11,dout
SetPin gp12,dout
SetPin gp13,dout
SetPin gp14,dout
SetPin gp15,dout
SetPin gp16,dout
SetPin gp17,dout
End Sub

Sub setsine
Dim a%(samples)
'L1
For i%=1 To samples
  a%(i%)=Int(resol*(1+Sin(i%*(2*Pi/samples))))
Next i%
'L2
For i%=1 To samples
  a%(i%)=a%(i%)+ 2*resol*Int(resol*(1+Sin(2*Pi/3 + i%*(2*Pi/samples))))
Next i%
'L3
For i%=1 To samples
  a%(i%)=a%(i%)+ (2*resol)*(2*resol)*Int(resol*(1+Sin(4*Pi/3 + i%*(2*Pi/samples))))
Next i%
End Sub

// 3 phase generator
// This is a 50Hz 3 phase (L1/L2/L3) generator running on ATMEGA328
// Outputs are 3x 6 bit ports, that need an external DAC (resistor network).
// In prototype setup 36k, 18k, 9.1k, (2.7+1.8)k, 2.2k, 1.1k where used with 1uF filter cap.
// Each sine wave consists of 128 samples.
// Uses a Timer 1 interrupt to output samples.

#include <TimerOne.h>
const int samples = 128;   // samples per sine
const int resolution = 31; // 6 bit resolution (5 bit and sine aplitude is +/- 1)  

int delay_tmp = (20000/samples);  // 50Hz = 20ms = 20000us
int Count;
byte L1[samples], L2[samples], L3[samples];


void setup() {
 // set IO pins:
 DDRD = DDRD | B11111100;  // for L3 set port D2...D7 output = pin 2..7
 DDRB = DDRB | B00111111;  // for L2 set port B0...B5 output = pin 8..13
 DDRC = DDRC | B00111111;  // for L1 set port C0...C5 output = pin A0..A5

 // generate data arrays for sine samples
 for (Count = 0; Count < samples; Count++) {
   L1[Count] = (byte) resolution * (1 + sin(2*PI*Count/samples));  
   L2[Count] = (byte) resolution * (1 + sin((2*PI*Count/samples) + 2*PI/3));  
   L3[Count] = (byte) resolution * (1 + sin((2*PI*Count/samples) - 2*PI/3));  
 }  

/*  // for debug
   Serial.begin(9600);
   for (Count = 0; Count < samples; Count++) {
     Serial.print(L1[Count],L2[Count],L3[Count],"\r");  
     delay(10);  
   }  */
 
 Timer1.initialize(delay_tmp); //set Timer 1 for 156uS interrupts (@128 samples)
 Timer1.attachInterrupt( T1_ISR ); // start interrupt
}

void loop() {
 // do nothing
}

void T1_ISR() {
   // send new samples out
   PORTC = L1[Count];
   PORTB = L2[Count];
   PORTD = (PIND & 0x03) + (L3[Count] << 2);

   // prepare for next samples
   Count++;
   Count = Count & (samples-1);
}

' PIO program that can output 50/60Hz squarewave on GP0-2 (3 pins > 3 phases)
Option Explicit

DIM integer asmblock(7)

VAR RESTORE         ' Retrieve PIO code into asmblock()

' Preparations : reserve GP0-2 for PIO
SetPin 1,pio0
SetPin 2,pio0    ' Pin 3 Gnd
SetPin 4,pio0

PIO clear 0
PIO PROGRAM 0,asmblock()

' Set clock 5kHz for 50Hz on pio0 sequencer 0
' or change frequency to 6kHz for 60Hz
' Assign 3 pins to SET group and assign a base of 0.
PIO init machine 0,0,5000,pio(pinctrl 0,3,0,0,0,0)

' Start the output
PIO start 0,0

PIO execute 0,0,0
Do
   Print ".";  ' do something to show we are working...
   Pause 1000
Loop
----------------------------
PIO Assembler:
Data "set pindirs 7"
Data "set pins 5 [16]"   ' Pins 1 & 4
Data "set pins 1 [15]"   ' Pin  1
Data "set pins 3 [16]"   ' Pins 1 & 2
Data "set pins 2 [15]"   ' Pin  2
Data "set pins 6 [16]"   ' Pins 2 & 4
Data "set pins 4 [15]"   ' Pin  4
Data "jmp 1"
Data ""

' Data contained in asmblock()
' and VAR SAVEd by the assembler program
&HF003EF01F005E087
&H0001EF04F006EF02
6 @ &HA042A042A042A042 nops
----------------------------

// 3 phase generator
// This is a 50Hz 3 phase (L1/L2/L3) generator running on ATMEGA328
// Outputs are 3x 6 bit ports, that need an external DAC (resistor network).
// In prototype setup 36k, 18k, 9.1k, (2.7+1.8)k, 2.2k, 1.1k where used with 1uF filter cap.
// Each sine wave consists of 128 samples.
// Uses a Timer 1 polled for most accurate timing.

const int samples = 128;   // samples per sine
const int resolution = 31; // 6 bit resolution (5 bit and sine aplitude is +/- 1)  

int delay_tmp = (20000/samples);  // 50Hz = 20ms = 20000us
int Count;
byte L1[samples], L2[samples], L3[samples];


void setup() {
 // set IO pins:
 DDRD = DDRD | B11111100;  // for L3 set port D2...D7 output = pin 2..7
 DDRB = DDRB | B00111111;  // for L2 set port B0...B5 output = pin 8..13
 DDRC = DDRC | B00111111;  // for L1 set port C0...C5 output = pin A0..A5

 // generate data arrays for sine samples
 for (Count = 0; Count < samples; Count++) {
   L1[Count] = (byte) resolution * (1 + sin(2*PI*Count/samples));  
   L2[Count] = (byte) resolution * (1 + sin((2*PI*Count/samples) + 2*PI/3));  
   L3[Count] = (byte) resolution * (1 + sin((2*PI*Count/samples) - 2*PI/3));  
 }  

/*  // for debug
   Serial.begin(9600);
   for (Count = 0; Count < samples; Count++) {
     Serial.print(L1[Count],L2[Count],L3[Count],"\r");  
     delay(10);  
   }  */

 // stop all interrupts
 noInterrupts();  

 // initialize timer 1 in phase correct PWM mode at 0.5us tick, due to symetry this is 1us
 ICR1 = delay_tmp;             // set TOP to delay_tmp
 TCCR1A = 0x00;                // Timer1 Control Reg A: Normal port operation, Wave Gen Mode normal
 TCCR1B = _BV(WGM13);          // set mode 8: phase and frequency correct pwm, stop the timer
 TCNT1  = 0;                   // Reset Timer Count to 0
 TCCR1B |= (1 << CS11);        // 8 prescale
}

void loop() {
   // in fastest possible loop check timer 1 reach bottom
   while (!(TIFR1 & _BV(TOV1))) { };
   TIFR1 |= _BV(TOV1); // clear TOV1 by writing 1 to it
   
   // send new samples out
   PORTC = L1[Count];
   PORTB = L2[Count];
   //PORTB = (PINB ^ B00111111); // debug at D13 for phase jitter
   PORTD = (PIND & 0x03) + (L3[Count] << 2);

   // prepare for next samples
   Count++;
   Count = Count & (samples-1);
}