Step Motor Driving Problem

[rezaf]

Hi friends,
I have a stepper motor driving project but have problem with steps. please see my circuit and code and say to me if you see problems.
Very Thanks. (source code written with mikroc)

char uart_rd[5];
char uart_rd2[5];
int i;
char FullStepForward [4]={0x01, 0x02, 0x04, 0x08};
char FullStepBackward[4]={0x09, 0x0C, 0x06, 0x03};


void MotorCW()
{

if(i<4){
PORTC = FullStepForward ;
delay_ms(100);
}
else if(i>4) i=0;
i++;
}

void MotorCCW()
{
if(i<4){
PORTC=FullStepBackward;
delay_ms(100);
}
else if(i>4) i=0;
i--;
}

void main() {
ADCON1 = 0b00000111;
CCP1CON = 0x00;
TRISB1_bit = 0x00; //output
TRISB2_bit = 0x00;
TRISB3_bit = 0x00;
TRISB4_bit = 0x00;
TRISB5_bit = 0x00;
PORTB = 0;
TRISC0_bit = 0x00; //output
TRISC1_bit = 0x00;
TRISC2_bit = 0x00;
TRISC3_bit = 0x00;
PORTC = 0;
i=0;
UART1_Init(9600); // Initialize UART module at 9600 bps
Delay_ms(100); // Wait for UART module to stabilize

while (1) {

if (UART1_Data_Ready() == 1) { // if data is received
uart_rd[1] = UART1_Read(); // reads text until command is found
}


switch(uart_rd[1]){
case 0x50: //Motor-CW(P)
MotorCW();
break;
case 0x48: //Motor-CCW(H)
MotorCCW();
break;
}
uart_rd[1] = 0;
}
}

 

[raco_rage]

Firstly, UART_rd[1] = 0 would not allow the control to go through the switch case. So it would go to the switch case only once, move one step and wait for the input to arrive.

secondly, (very minor) your motor wont do anything for i==4.

 

[rezaf]

Thanks, I corrected the problems that you said but don't know why the motor rotate 2.7 degree in CW and 2.7 degree in CCW and with more commands return, (I want the motor rotate 1.8 degree with every command until a 360 degree revolution completes, can you help me?

 

[raco_rage]

if(i<4){
PORTC = FullStepForward ;
delay_ms(100);
}
else if(i>4) i=0;
i++;

In this case, i=0 is never reached. As soon as i=5, i=0 and then i++ makes it i=1. correct this and I think it would all work fine.

If you still have problems, post your new modified code.