CodeVision AVR Help - Electronic Circuits Projects Diagrams Free

hitusharpatil · 21st January 2008, 04:55 PM

Can anyone tell me how "printf" statement works in CodeVision AVR and after compling Where Can I see output

OR please tell me Why "printf" is use in Codevision AVR

BeeBop · 21st January 2008, 05:38 PM

Quote:

Originally Posted by hitusharpatil

Can anyone tell me how "printf" statement works in CodeVision AVR and after compling Where Can I see output

OR please tell me Why "printf" is use in Codevision AVR

I'm not sure about Codevisions printf function, but in general printf is formated printing. It uses putc, which directs the output stream to whatever you want. If your putc function is directed at an LCD, this is where it will show up. If it is directed at the serial port then sent to a PC, you can view the stream with a terminal program, etc.

Here is a simple example of a printf function with no strings and no floating point:

Code:

/*-----------------28.08.99 22:49-------------------
 *   Simple printf function (no fp, and strings)
 *--------------------------------------------------*/
int printf(const char *format, ...) {
  static const char hex[] = "0123456789ABCDEF";
  char format_flag;
  unsigned int u_val, div_val, base;
  char *ptr;
  va_list ap;

  va_start (ap, format);
  for (;;) {
     while ((format_flag = *format++) != '%') {      // Until '%' or '\0'
       if (!format_flag) {
         va_end (ap);
         return (0);
       }
       lcd_putch (format_flag);
     }

     switch (format_flag = *format++) {
       case 'c': format_flag = va_arg(ap,int);
       default:  lcd_putch(format_flag); continue;

       case 'd': base = 10; div_val = 10000; goto CONVERSION_LOOP;
       case 'x': base = 16; div_val = 0x10;

       CONVERSION_LOOP:
       u_val = va_arg(ap,int);
       if (format_flag == 'd') {
         if (((int)u_val) < 0) {
           u_val = - u_val;
           lcd_putch ('-');
         }
         while (div_val > 1 && div_val > u_val) div_val /= 10;
       }
       do {
         lcd_putch (hex[u_val / div_val]);
         u_val %= div_val;
         div_val /= base;
       } while (div_val);
    }

hitusharpatil · 21st January 2008, 06:11 PM

Quote:

Originally Posted by BeeBop

I'm not sure about Codevisions printf function, but in general printf is formated printing. It uses putc, which directs the output stream to whatever you want. If your putc function is directed at an LCD, this is where it will show up. If it is directed at the serial port then sent to a PC, you can view the stream with a terminal program, etc.

Here is a simple example of a printf function with no strings and no floating point:

Code:

/*-----------------28.08.99 22:49-------------------
 *   Simple printf function (no fp, and strings)
 *--------------------------------------------------*/
int printf(const char *format, ...) {
  static const char hex[] = "0123456789ABCDEF";
  char format_flag;
  unsigned int u_val, div_val, base;
  char *ptr;
  va_list ap;

  va_start (ap, format);
  for (;;) {
     while ((format_flag = *format++) != '%') {      // Until '%' or '\0'
       if (!format_flag) {
         va_end (ap);
         return (0);
       }
       lcd_putch (format_flag);
     }

     switch (format_flag = *format++) {
       case 'c': format_flag = va_arg(ap,int);
       default:  lcd_putch(format_flag); continue;

       case 'd': base = 10; div_val = 10000; goto CONVERSION_LOOP;
       case 'x': base = 16; div_val = 0x10;

       CONVERSION_LOOP:
       u_val = va_arg(ap,int);
       if (format_flag == 'd') {
         if (((int)u_val) < 0) {
           u_val = - u_val;
           lcd_putch ('-');
         }
         while (div_val > 1 && div_val > u_val) div_val /= 10;
       }
       do {
         lcd_putch (hex[u_val / div_val]);
         u_val %= div_val;
         div_val /= base;
       } while (div_val);
    }

Can you please tell me how can I see output of above program on PC?
What modifiactions should I do in the above code?

BeeBop · 21st January 2008, 06:19 PM

You don't need to add the function to your code; it is an example of how printf works. To direct your output to a PC, then write yourself a PC_putc() function which will direct its output to a serial stream using a UART if you have one on your chip. Which chip are you using?
I will try to find out more about codevision, if I can.

hitusharpatil · 21st January 2008, 06:27 PM

Quote:

Originally Posted by BeeBop

You don't need to add the function to your code; it is an example of how printf works. To direct your output to a PC, then write yourself a PC_putc() function which will direct its output to a serial stream using a UART if you have one on your chip. Which chip are you using?
I will try to find out more about codevision, if I can.

I am using Atmega32. Do I need to burn the cip and then see the output?

BeeBop · 21st January 2008, 06:31 PM

Looks like codevision has a wizard to set up a project to do this. I found this info on the IDE:

Quote:

Built-in CodeWizardAVR Automatic Program Generator, allows you to write in a matter of minutes all the code needed for implementing the following functions:

UART initialization and interrupt driven buffered serial communication with the following parameters: 7N2, 7E1, 7O1, 8N1, 8N2, 8E1 and 8O1

I downloaded the manual; I'll tell you more in a few minutes.

BeeBop · 21st January 2008, 06:33 PM

Quote:

I am using Atmega32. Do I need to burn the cip and then see the output?

Yes, you will have to do this in order for it to run (unless you are doing the project in simulation first.)

BeeBop · 21st January 2008, 06:41 PM

Hi again,
Get the manual here:
http://www.hpinfotech.ro/html/cvavr_doc.htm

and turn to page 113, which gives you details on using printf and the UART.

Do you know about AVR Freaks website?

http://www.avrfreaks.net/

hitusharpatil · 21st January 2008, 06:48 PM

Quote:

Originally Posted by BeeBop

Yes, you will have to do this in order for it to run (unless you are doing the project in simulation first.)

Suppose I burnt the program on chip now I want to see the output on PC.
So how can I interface Chip with PC to see output? What steps do i need to follow?

BeeBop · 21st January 2008, 07:29 PM

You will need some kind of level converter, such as Max 232, hooked up to your micro rx and tx pins. This tutorial should help:
http://www.sparkfun.com/commerce/pre...p?p=BEE-4-UART

There is another tutorial on using printf with the gcc compiler here:
http://www.sparkfun.com/commerce/pre...EE-5-Compiling

Hope this helps you get where you are going.

hitusharpatil · 21st January 2008, 08:05 PM

Quote:

Originally Posted by BeeBop

You will need some kind of level converter, such as Max 232, hooked up to your micro rx and tx pins. This tutorial should help:
http://www.sparkfun.com/commerce/pre...p?p=BEE-4-UART

There is another tutorial on using printf with the gcc compiler here:
http://www.sparkfun.com/commerce/pre...EE-5-Compiling

Hope this helps you get where you are going.

Now things are too much complicaetd for my Project. I have a project form net but thing is that it is very difficult for me to proceed. will you please guide me?

BeeBop · 21st January 2008, 09:29 PM

Well, I haven't done much of anything with AVR, but can try...

What project are you working on?

hitusharpatil · 22nd January 2008, 04:09 AM

Quote:

Originally Posted by BeeBop

Well, I haven't done much of anything with AVR, but can try...

What project are you working on?

I am working on "Voice command Recognition System" using Atmega32 to glow LED at output Port. I have similar project with code but as I am new in this field I cant proceed properly.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Latest
AVR (tiny85) differing output on pins...	magician13134	Electronic Projects Design/Ideas/Reviews	7	24th January 2008 11:13 PM
pic or avr	umar karim	Micro Controllers	11	21st January 2008 06:30 PM
AVR DDS ~ RS232 problem...	krazatchu	Micro Controllers	15	13th December 2007 04:44 AM
How does the AVR do one clock per instruction?	blueroomelectronics	Micro Controllers	5	9th December 2007 01:29 AM
Eclipse IDE for ARM, AVR, and PIC?	linuxguy	Micro Controllers	9	29th September 2007 05:13 PM

21st January 2008, 04:55 PM	(permalink)
hitusharpatil	CodeVision AVR Help Can anyone tell me how "printf" statement works in CodeVision AVR and after compling Where Can I see output OR please tell me Why "printf" is use in Codevision AVR

21st January 2008, 06:19 PM	(permalink)
BeeBop	You don't need to add the function to your code; it is an example of how printf works. To direct your output to a PC, then write yourself a PC_putc() function which will direct its output to a serial stream using a UART if you have one on your chip. Which chip are you using? I will try to find out more about codevision, if I can.

21st January 2008, 06:41 PM	(permalink)
BeeBop	Hi again, Get the manual here: http://www.hpinfotech.ro/html/cvavr_doc.htm and turn to page 113, which gives you details on using printf and the UART. Do you know about AVR Freaks website? http://www.avrfreaks.net/

21st January 2008, 07:29 PM	(permalink)
BeeBop	You will need some kind of level converter, such as Max 232, hooked up to your micro rx and tx pins. This tutorial should help: http://www.sparkfun.com/commerce/pre...p?p=BEE-4-UART There is another tutorial on using printf with the gcc compiler here: http://www.sparkfun.com/commerce/pre...EE-5-Compiling Hope this helps you get where you are going.

21st January 2008, 09:29 PM	(permalink)
BeeBop	Well, I haven't done much of anything with AVR, but can try... What project are you working on?