Simple LEB blinking problem

Status
Not open for further replies.
M

MrNobody

New Member
The code below is a simple one to turn the LED on for 1 second and then off for 1 second. External crystal of 10MHz is used and the PLL is turned on which brings the FOSC up to 40MHz. However when I program and run the code, The LED appears to stay ON for only 1/4 of a second.
Am I missing something..? Thanks.

Code: 
#include <p18F4620.h>
#include <delays.h>
#include <stdio.h>

#pragma config WDT = OFF
#pragma config MCLRE = ON
#pragma config LVP = OFF
#pragma config OSC = HSPLL
#define CLOCK_FREQ		(40000000ul)      // Hz 

void main()
{
	TRISB = 0x00;
	while(1)
	{
		PORTBbits.RB0 = 1;
		Delay10KTCYx(1000);
		PORTBbits.RB0 = 0;
		Delay10KTCYx(1000);
	}
}
 
Hi,
I don't use C18. Is it because Delay10KTCYx works up to 255 only? I mean Delay10KTCYx(255).
Use LAT registers for outputting as good practice, but it's okay here.
 
Sorry for double post..
Refer to the post below..
 

Attachments

  • LED Blink.zip
    538 bytes · Views: 153
Last edited:
Thanks..
In the code below, I have commented the PLL and change the FOSC to 10MHZ. Again, I use 10MHz crystal for the PIC. I have also changed the delay from 1000 to 250 so that it is within 8 bit. Again, the code is to turn the LED ON for 1 second and then OFF for 1 second. However, the problem still remain..
BTW, I am using C18 compiler.
I have also attached the hex file and the asm code.


Code: 
#include <p18F4620.h>
#include <delays.h>
#include <stdio.h>

#pragma config WDT = OFF
#pragma config MCLRE = ON
#pragma config LVP = OFF
//#pragma config OSC = HSPLL
#define CLOCK_FREQ		(10000000ul)      // Hz 

void main()
{
	TRISB = 0x00;
	while(1)
	{
		PORTBbits.RB0 = 1;
		Delay10KTCYx(250);
		PORTBbits.RB0 = 0;
		Delay10KTCYx(250);
	}
}

Code in asm.
Code: 
1:                 #include <p18F4620.h>
2:                 #include <delays.h>
3:                 #include <stdio.h>
4:                 
5:                 #pragma config WDT = OFF
6:                 #pragma config MCLRE = ON
7:                 #pragma config LVP = OFF
8:                 //#pragma config OSC = HSPLL
9:                 #define CLOCK_FREQ		(10000000ul)      // Hz 
10:                
11:                void main()
12:                {
13:                	TRISB = 0x00;
  00F8    6A93     CLRF 0xf93, ACCESS
14:                	while(1)
  0112    D7F3     BRA 0xfa
15:                	{
16:                		PORTBbits.RB0 = 1;
  00FA    8081     BSF 0xf81, 0, ACCESS
17:                		Delay10KTCYx(250);
  00FC    0EFA     MOVLW 0xfa
  00FE    6EE6     MOVWF 0xfe6, ACCESS
  0100    EC65     CALL 0xca, 0
  0102    F000     NOP
  0104    52E5     MOVF 0xfe5, F, ACCESS
18:                		PORTBbits.RB0 = 0;
  0106    9081     BCF 0xf81, 0, ACCESS
19:                		Delay10KTCYx(250);
  0108    0EFA     MOVLW 0xfa
  010A    6EE6     MOVWF 0xfe6, ACCESS
  010C    EC65     CALL 0xca, 0
  010E    F000     NOP
  0110    52E5     MOVF 0xfe5, F, ACCESS
20:                	}
21:                }	
  0114    0012     RETURN 0
 

Attachments

  • LED Blink.zip
    538 bytes · Views: 131
I had a problem on the PIC12F629 that the LEDs wouldnt flash. I solved it by putting :
Code: 
 GPIO = 0;               // Turn off all pins

so in your casae try putting this line in after your trisb line:
Code: 
PORTB = 0;               // Turn off all pins
 
i have a problem

hi every one i have aproblem of this code , but i dont know what it is i need some one to help me please

void main()
{
PORTB=0;
TRISB=0;//as output
TRISD=1;//as input
while(1)
{
if (PORTD.f1=1)
PORTB.f7=1 ;
else
PORTB.f7=0;



}
}
 
MedoLee said:
hi every one i have aproblem of this code , but i dont know what it is i need some one to help me please

void main()
{
PORTB=0;
TRISB=0;//as output
TRISD=1;//as input
while(1)
{
if (PORTD.f1=1)
PORTB.f7=1 ;
else
PORTB.f7=0;



}
}
Click to expand...

I am assuming you are using mikroC compiler.
Try this
Code: 
void main()
{
PORTB=0;
TRISB=0;//as output
TRISD=[B]2[/B];//as input
while(1)
{
 if (PORTD.f1=1)
        PORTB.f7=1 ;
 else
        PORTB.f7=0;
}
}

You wanted to use RD1 as input but you are setting RD0 as input instead. So I changed it for you.
 
try to use this:
Code: 
void main()
{
PORTB=0;
TRISB=0;//as output
TRISD=1;//as input
PORTB=0; // turn off all pins
PORTD=0: // turn off all pins
while(1)
{
if (PORTD.f1=1){
PORTB.f7=1 ;
}
else
{
PORTB.f7=0;
}


}
}
 
Somehow (and i dont know why yet) you have turn off all ports or set all registers with all 0.

MedoLee:
If you are using MikroC you have to set the config parameterse correctly ( that can be hard if its you first time)
 
And using
Code: 
 TRISD=2 // just plain stupid
Wont work as the registers are binary alternatively you can use the hex value of the pins you want to use :
if you want to use pins 2 and 4 as inputs and the rest as inputs it would look like this binary 00101000 and hex it would be 0x28
Code: 
TRISD= 00101000 // or in hex
TRISD=0x28
 
Hey you're insulting. Besides,
Code: 
TRISD=2
is working. decimal 2 = 0b10 = 0x2

If you want to use pin 2 and 4 as inputs,
Code: 
TRISD = 0b00010100;
TRISD = 0x14;
TRISD = 20;
are the same.
 
Each instruction takes 4 clock cycles and so if you have a 10MHz crystal and the PLL at *4 to get 40MHz, you will only get 10M instructions per second. Without the PLL you get 2.5M instructions.

Edit, just realised you have taken this into account. I think bananasoing is on the right track. OSC=HS; is still required.

Mike.
 
Last edited:
Pommie said:
Each instruction takes 4 clock cycles and so if you have a 10MHz crystal and the PLL at *4 to get 40MHz, you will only get 10M instructions per second. Without the PLL you get 2.5M instructions.

Mike.
Click to expand...
Yeah...
With each instructions being 1/2.5M, or 0.4us, for the LED to remain ON for 1 second, i need to use a delay of 2.5M instructions right..?
Thats why i use Delay10KTCYx(250) cause 10K x 250 = 2.5M.
However, my LED only remains ON for only 1/4 or 1/2 of that time..
 
1/4 or 1/2? The delay time is not constant?
 
The delay is constant.. Its just that I don't have an oscilloscope so I can't tell the pulse width whether it is 1/4 or 1/2..

Anyway.. it is very strange as I have just run the code but this time, it works.. The LED remain on for 1 second. I did not add anything or change anything since the last time i posted.

However, as per the coding, the coding is correct right..? I mean, the delay etc..
 
Correction to the previous post.
I did make some changes.. I added the #pragma config OSC = HS and it works..
Thanks bananasiong..
 
Status
Not open for further replies.

Similar threads

W
  • Question
C18 problem
Replies
10
Views
3K
Nigel Goodwin
O
  • Question
ESP32-CAM problem after uploading
Replies
5
Views
1K
ZipZapOuch
P
Weird delay problem.
Replies
13
Views
3K
Pommie
P
  • Question
The LCR T4 problem after the program firmware does not know the capacitor
Replies
8
Views
2K
electronium
Need some heads.. Logic problem I have spent days on
Replies
12
Views
4K
Nigel Goodwin
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…