• State Not Answered
  • Locked Locked
  • Replies 8 replies
  • Subscribers 21 subscribers
  • Views 2459 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

printf doesn't work !

Christophe Champigny

I don't know why, I would like to implement a printf function in my C program for my T89C51CC01. When I run the debugger, my program stop during the execution of the printf function.

The manual say that printf use the putchar function. OK. I try to take a look on the disassembly windows, and the program stop just when it tries to send the first character of my string.

This is a sample of my program:

void main(void)
{
while(1)
{
// Fonctionnement normal

// Mode de configuration
modeConfig = 1;
init_mode_config();
TR0 = 1;
while(modeConfig == 1)
{
switch(niveauMenu)
{
// Attente des caractères CR,CR pour activer le menu
case 0x00:	if(flgDataRecu)		// Test si le mode config a bien été demandé ?
							{					// Attente de 2 CR
								flgDataRecu = 0;

								if(cara_recu == CR)
								{
									temps = 0;
									if(flgDemandeMenu == 1)
									{
										TR0 = 0;
										niveauMenu = 0x01;
									}
									else
										flgDemandeMenu = 1;
								}
								else
								{
									if(flgDemandeMenu == 1)
										flgDemandeMenu = 0;
									// Mauvais caractère !
								}
							}
							break;

				// Menu principal
				case 0x01:	printf("\n---------- STDI ----------", table_divers[1], "\n\n"); //
							printf("A - Vitesse de Transmission serie\n");
							printf("B - Format des Donnees\n");

Parents
  • 0

    First, fix your indenting please. 4 spaces (never tabs!) per indent only. This is my law, I expect the world to abide by it. :-)

    Second,

    printf("\n---------- STDI ----------", table_divers[1], "\n\n");
    What the heck is this? Printf needs a format specifier which you omitted, fix that first. The table_drivers[] needs its value placed somewhere. If it is an array of int's then add a %d.

    Goodness, just type this assuming that table drivers is an array of int's and please lookup printf in your C reference.

    printf("\n---------- STDI ----------\n%d\n\n", table_divers[1]);
    I suspect printf works just fine when called properly.

    Regards,

    - Mark

Reply
  • 0

    First, fix your indenting please. 4 spaces (never tabs!) per indent only. This is my law, I expect the world to abide by it. :-)

    Second,

    printf("\n---------- STDI ----------", table_divers[1], "\n\n");
    What the heck is this? Printf needs a format specifier which you omitted, fix that first. The table_drivers[] needs its value placed somewhere. If it is an array of int's then add a %d.

    Goodness, just type this assuming that table drivers is an array of int's and please lookup printf in your C reference.

    printf("\n---------- STDI ----------\n%d\n\n", table_divers[1]);
    I suspect printf works just fine when called properly.

    Regards,

    - Mark

Children
  • 0 in reply to Mark Odell

    Hi Mark, thanks for your help!
    (I'm agree with you about the indenting but my copy and paste do that)
    the 

     table_divers[1]
    is another string, so i can accumulate it in my printf.

    It seems to me that my problem is essentially hardware! I do many investigation and i find a really strange solution!!! See what i need to do to execute my printf function:

    void main(void)
    {
    while(1)
    {
    // Fonctionnement normal

    // Mode de configuration
    modeConfig = 1;
    init_mode_config();
    TR0 = 1;
    while(modeConfig == 1)
    {
    switch(niveauMenu)
    {
    // Attente des caractères CR,CR pour activer le menu
    case 0x00:
    .
    .
    .
    break;
    // Menu principal
    case 0x01:
    ES = 0;
    TI = 1;
    printf("\n---------- STDI ----------", table_divers[1], "\n\n");
    printf("A - Vitesse de Transmission serie\n");
    printf("B - Format des Donnees\n");
    .
    .
    .
    .

    After disable the serial interruption and set the TI flag, all printf execute correctly !!!! That's really strange !!!!

  • 0 in reply to Mark Odell

    Hi Mark, thanks for your help!
    (I'm agree with you about the indenting but my copy and paste do that)
    the 

     table_divers[1]
    is another string, so i can accumulate it in my printf.

    It seems to me that my problem is essentially hardware! I do many investigation and i find a really strange solution!!! See what i need to do to execute my printf function:
    void main(void)
{
while(1)
{
// Fonctionnement normal

// Mode de configuration
modeConfig = 1;
init_mode_config();
TR0 = 1;
while(modeConfig == 1)
{
switch(niveauMenu)
{
// Attente des caractères CR,CR pour activer le menu
case 0x00:
.
.
.
break;
// Menu principal
case 0x01:
ES = 0;
TI = 1;
printf("\n---------- STDI ----------", table_divers[1], "\n\n");
printf("A - Vitesse de Transmission serie\n");
printf("B - Format des Donnees\n");
.
.
.
.
    After disable the serial interruption and set the TI flag, all printf execute correctly !!!! That's really strange !!!!

    sorry for the double post.

  • 0 in reply to Christophe Champigny 

    printf("\n---------- STDI ----------", table_divers[1], "\n\n");
    This is still wrong, at least if it works it's a surprise. Please correct this by typing this instead:
    printf("\n---------- STDI ----------%s\n\n", table_divers[1]);
    After disable the serial interruption and set the TI flag, all printf execute correctly !!!! That's really strange !!!!

    Not strange at all. Did you write a serial ISR? If so, you must re-write putchar() yourself to use your interrupt based serial port. Printf() calls putchar() so you just need to re-write putchar().

    If you did not have a serial ISR with putchar/getchar re-written to use it then printf/scanf should not work.

    - Mark

  • 0 in reply to Mark Odell

    That's right! I write a serial ISR in my program!
    OK i understand better the putchar function and my ISR are in conflict. OK

    Sorry for my mistake about the printf parameter, your're right again.

    Thanks a lot, it will be easier now.

  • 0 in reply to Christophe Champigny

    Extra arguments in the call to printf are ignored if there are no format specifiers. So it could not be the problem.

    - Mike

  • 0 in reply to Mik Kleshov

    Right! That's what's happened to me, but I corrected it now...