The logic inside the PastEtruder

As the electronics was a little bit bigger, the code is also a bit longer...

The PastEdruder is programed with MPLAB-X and the XC8 compiler, the same combination i used for the Fab-Pic. In fact it is the same controller...

First make some configuration-settings and define some names for the pins to make the code more readable:

#define RS PORTCbits.RC2
#define EN PORTCbits.RC3
#define D4 PORTCbits.RC4
#define D5 PORTCbits.RC5
#define D6 PORTCbits.RC6
#define D7 PORTCbits.RC7
#define heater_1 PORTCbits.RC0
#define heater_2 PORTCbits.RC1
#define stepper_dir PORTAbits.RA3
#define stepper_step PORTAbits.RA5
#define spritze_dir PORTBbits.RB7
#define spritze_pwm PORTBbits.RB6
#define btn_up PORTBbits.RB5
#define btn_down PORTBbits.RB4
#define btn_left PORTBbits.RB3
#define btn_right PORTBbits.RB2
#define external_dir PORTBbits.RB1
#define external_step PORTBbits.RB0

#pragma config FOSC = HS1 //extern oszilator 4-16mhz
#pragma config PLLCFG = ON //PLL enable, CPU=32 MHz
#pragma config PWRTEN = ON //PowerOnTimer on
#pragma config WDTEN = OFF //Watchdog Timer off
#pragma config XINST = OFF //Extended Instruction Set off, no support by free compiler
#pragma config SOSCSEL = DIG //PORTC.0 and PORTC.1 digital I/O, not second oszilator


As you can see, almost all pins are used. RS, EN, D4 to D7 are used for the display.

After this we define some globale variables:

int temp_1_ist, temp_2_ist;
int temp_1_soll = 2045;
int temp_2_soll = 2045;
int motor_current_ist;
int motor_current_soll = 0;
int temp;
int menue = 0;
int stepper_manual = 0;
int lcd_in_progress = 0;
float temp_1_ist_display = 20;
float temp_2_ist_display = 20;
int temp_1_soll_display = 20;
int temp_2_soll_display = 20;


Folowed by two subroutines: temp_read and temp_check.
temp_read just starts the ADCs and read in the values for both heaters and the motor-current:

void temp_read(void)
{
ADCON0 = 0b00000001; //Select AD-Channel 0
ConvertADC(); //start AD-Conversion
while(BusyADC()); //wait for conversion to finish
temp_1_ist = ((ADRESH)<<8)|(ADRESL); //read in the result

ADCON0 = 0b00000101; //Select AD-Channel 1
ConvertADC(); //start AD-Conversion
while(BusyADC()); //wait for conversion to finish
temp_2_ist = ((ADRESH)<<8)|(ADRESL); //read in the result

ADCON0 = 0b00001001; //Select AD-Channel 2
ConvertADC(); //start AD-Conversion
while(BusyADC()); //wait for conversion to finish
motor_current_ist = ((ADRESH)<<8)|(ADRESL); //read in the result*/
}

temp_check is a kind of controller for the heaters and the dc-motor. It should be a PID-style, but it is only the Quick-n-Dirty solution. Works fine!

void temp_check(void){
temp_read();
if (temp_1_ist <= (temp_1_soll)) heater_1 = 1;
else heater_1 = 0;

if (temp_2_ist <= (temp_2_soll)) heater_2 = 1;
else heater_2 = 0;

if ((motor_current_ist <= motor_current_soll) && !stepper_manual) spritze_pwm = 1;
else spritze_pwm = 0;
}

temp_check is called by a timer-interrupt every 5ms. This way the heaters are safe for overheating and the controller works without the PID


In the main-loop first some variables are setuped, the ADCs and timers are configured and the pins are configured as In- or Outputs:

//CONFIG ADCs
ANCON0 = 0b00000111; // Just AN0 AN1 AN2 are an analog input, all other pins are digital
ANCON1 = 0b00000000;
ADCON1 = 0b00000000; //No special triggers, Ref is Vdd and Vss
ADCON2 = 0b10111100; //result is right justified, 8 Tads, Clock = 32Mhz / 4

//config outputs
LATCbits.LATC2 = 0;TRISCbits.TRISC2 = 0; //LCD
LATCbits.LATC3 = 0;TRISCbits.TRISC3 = 0; //LCD
LATCbits.LATC4 = 0;TRISCbits.TRISC4 = 0; //LCD
LATCbits.LATC5 = 0;TRISCbits.TRISC5 = 0; //LCD
LATCbits.LATC6 = 0;TRISCbits.TRISC6 = 0; //LCD
LATCbits.LATC7 = 0;TRISCbits.TRISC7 = 0; //LCD
LATCbits.LATC0 = 0;TRISCbits.TRISC0 = 0; //heater_1
LATCbits.LATC1 = 0;TRISCbits.TRISC1 = 0; //heater_2
LATAbits.LATA5 = 0;TRISAbits.TRISA5 = 0; //Stepper Step
LATAbits.LATA3 = 0;TRISAbits.TRISA3 = 0; //Stepper dir
LATBbits.LATB7 = 0;TRISBbits.TRISB7 = 0; //Spritze dir
LATBbits.LATB6 = 0;TRISBbits.TRISB6 = 0; //Spritze dir

//config inputs
LATBbits.LATB5 = 0;TRISBbits.TRISB5 = 1; //button up
LATBbits.LATB4 = 0;TRISBbits.TRISB4 = 1; //button down
LATBbits.LATB3 = 0;TRISBbits.TRISB3 = 1; //button left
LATBbits.LATB2 = 0;TRISBbits.TRISB2 = 1; //button right
LATBbits.LATB1 = 0;TRISBbits.TRISB1 = 1; //external_dir
LATBbits.LATB0 = 0;TRISBbits.TRISB0 = 1; //external step

//Timer1 for step-driver
T1CON = 0b00000011; //Config Timer1
IPR1bits.TMR1IP = 1; //Setting Timer1 to high-prio
PIE1bits.TMR1IE = 0; //Disable Timer1 Interrupt
PIR1bits.TMR1IF = 0; //rest TMR1-Interrupt flag

RCONbits.IPEN = 1; //enable High/Low-Prio
ei(); // master switch to enable interrupt
INTCONbits.GIE_GIEH = 0; //disable all High-Prio-Interrupts
INTCONbits.PEIE_GIEL = 1; //enable all Low-Prio-Interrupts

After this the LCD is fired with data for the first time. Not a big deal with the XC8-included lib:

// LCD Init
Lcd_Init();
sprintf(s, "This is ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, "PastExtruder!");
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);

As you can see, first a string is filled with sprintf, then this string is send to the display after setup which line should be used.

Then the program loops in a while-loop. Every time it loops the buttons left and right are read in to setup a variable called "menue". With this variable is choosed which menu-display is active.
No matter in which menu-mode you are, the timer-interrupt lets the pic check the temperature of the heaters every 5ms...
The code is mainly commentaded and easy to read i think, so here it is:

if (menue == 0) //show the actual temperatures and the motor-current
{
INTCONbits.GIE_GIEH = 1; //enable all High-Prio-Interrupts
if (temp_soll_update == 1){
saved_temp_1 = (temp_1_soll_display / 0.265) + 1970;
saved_temp_2 = (temp_2_soll_display / 0.265) + 1970;
temp_1_soll = saved_temp_1;
temp_2_soll = saved_temp_2;
temp_soll_update = 0;
}
saved_temp_1 = temp_1_ist;
saved_temp_2 = temp_2_ist;
temp_1_ist_display = (saved_temp_1 - 1970) * 0.265;
temp_2_ist_display = (saved_temp_2 - 1970) * 0.265;
sprintf(s, " T1 T2 MC ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, "%2.1f %2.1f %i ", temp_1_ist_display, temp_2_ist_display, motor_current_ist);
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);
sleep(250);
}

if (menue == 1) //setup the temperature of heater 1
{
INTCONbits.GIE_GIEH = 0; //disable all High-Prio-Interrupts
sprintf(s, "Temp 1: ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, "%i deg. C ", temp_1_soll_display);
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);
if (btn_up == 0) {
temp_1_soll_display++;
temp_soll_update = 1;

sleep (100);
}
if (btn_down == 0) {
temp_1_soll_display--;
temp_soll_update = 1;
sleep (100);
}
}

if (menue == 2) //setup the temperature of heater 2
{
INTCONbits.GIE_GIEH = 0; //disable all High-Prio-Interrupts
sprintf(s, "Temp 2: ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, "%i deg. C ", temp_2_soll_display);
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);
if (btn_up == 0) {
temp_2_soll_display++;
temp_soll_update = 1;

sleep (100);
}
if (btn_down == 0) {
temp_2_soll_display--;
temp_soll_update = 1;
sleep (100);
}
}

if (menue == 3) //setup the motor-current
{
INTCONbits.GIE_GIEH = 0; //disable all High-Prio-Interrupts
sprintf(s, "Motor Current: ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, "%i mA ", motor_current_soll);
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);
if (btn_up == 0) {
motor_current_soll++;
sleep (100);
}
if (btn_down == 0) {
motor_current_soll--;

sleep (100);
}
}

if (menue == 4) //drive the motors by hand to fill-in material
{
INTCONbits.GIE_GIEH = 1; //enable all High-Prio-Interrupts
sprintf(s, "Manual drive ");
Lcd_Set_Cursor(1,1);
Lcd_Write_String(s);
sprintf(s, " ");
Lcd_Set_Cursor(2,1);
Lcd_Write_String(s);
if (btn_up == 0) {
spritze_dir = 1;
stepper_dir = 1;
spritze_pwm = 1;
stepper_manual = 1;
while (!btn_up){
if (motor_current_ist >= motor_current_soll) spritze_pwm = 0;
else spritze_pwm = 1;
}
}
if (btn_down == 0) {
spritze_dir = 0;
stepper_dir = 0;
spritze_pwm = 1;
stepper_manual = 1;
while (!btn_down){
if (motor_current_ist >= motor_current_soll) spritze_pwm = 0;
else spritze_pwm = 1;
}
}
stepper_manual = 0;
spritze_pwm = 0;
}

if (!btn_left) {
menue--;
if (menue < 0) menue = 4;
while (!btn_left);
sleep (100);
}

if (!btn_right) {
menue++;
if (menue >= 5) menue = 0;
while (!btn_right);
sleep (100);
}

Finaly there is the code for the external-interrupt. This Pin is connected to the step-signal of my smoothie-board and reads in the extruder-commands writen in the g-code:

if (INTCONbits.INT0IF == 1)
{
stepper_dir = external_dir;
stepper_step = external_step;
if (INTCON2bits.INTEDG0 == 0) INTCON2bits.INTEDG0 = 1;
else INTCON2bits.INTEDG0 = 0;
INTCONbits.INT0IF = 0;
}

Thats all, wasn´t too much, don´t you think ;)

And here is the whole mplab-project-folder for you to download: ZIP-File