desperate need of help urgent with microcontrollers

[Vandal S]

uart1_read mikroc

i need urgent with a problem that i can't undestand. i am a beginner so you can expect that i made huge errors, but please help me because i have an exam in a couple of days

i wrote a program in mikroc, which gets a character by USART and starts 4 leds (actually there are 2 motors, but for the simplicity i removed that circuit). i used interrupts and delays.
the problem is that if i limit the current to a very low value, even the leds don't light, but they blink rapiddly according to my program. so they work ok.
but if i increase the current, they behave strangely. i press (as it is pc controlled) to go left and it remains in left. the same is for right. i press up, it randomly activates left, then a little back so the motors stops, then up again.. i haven't seen a perfect pattern, just that most of the time (not always) left and right are activated at the right time, but they stay forever.
i don't think it's a rf problem (there are rf modules between pc and pic 16f877) because at very low current (<50mA) they blink as they should.
the program i think is good, because in proteus works

it could be that it's not filtered enough? but i put 2 capacitors at the 7805, 2 at the oscillator..

please, once again, help me with an ideea, something. at least to know the cause, if not to solve it.

 

[blueroomelectronics]

Post your schematic & code

 

[Vandal S]

char byte_read, i = 0, flag = 0;
unsigned short cnt = 0;
#define Dir PORTD
#define front 0b00000001
#define left 0b00000010
#define back 0b00000100
#define right 0b00001000
#define Stop 0b00000000
#define backleft 0b00000110
#define backright 0b00001100
#define frontleft 0b00000011
#define frontright 0b00001001

void interrupt ()
{
PIR1.TMR1IF = 0;
if (PIR1.RCIF)
{
byte_read = UART1_READ();
flag = 1;
}
} end interrupt


void main ()
{
unsigned short j;
TRISD = 0;
INTCON.PEIE = 1;
T1CON = 1;
PIE1.RCIE = 1;
PIE1.TMR1IE = 1;
INTCON.GIE = 1;

UART1_Init(1200);

while(1)
{
if (flag ==1)
{switch(byte_read)
{
case 'W':{
Dir=front;
flag=0;
delay_ms(420);
break;
}
case 'S':{
Dir=back;
flag=0;
delay_ms(420);
break;
}

...



}
}
if (flag==0)
Dir=Stop;
}
}