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Show a value on lcd, got a "/" :(

 
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quichedood



Joined: 02 Feb 2004
Posts: 5

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Show a value on lcd, got a "/" :(
PostPosted: Mon Feb 02, 2004 3:09 pm     Reply with quote
hi everybody,

i'm new to ccs, and i try to realize my project.
i've done some functions who works but i'm locked on something who looks very easy :p

so here a part of my code :

Code:

int temperature;
char mystring[21];

//send a char to lcd
void send_char(char str_eight){
   output_high(LCD_RS);
   trait_eight = align1(str_eight);
   OUTPUT_A (trait_eight);
   enable_lcd();

   trait_eight = align2(str_eight);
   OUTPUT_A (trait_eight);
   enable_lcd();
}

//Send a value to lcd
void send_value(int value){
   sprintf(mystring,"%u",value);
   send_char(mystring);
}

temperature = 65;
send_value(temperature);



ok so here is the problem the function "send_char" works fine
example : send_char("test"); -> "test" is writtent on my lcd

BUT, now i would like to show the content of "temperature" (who's 65)
so i use the other function : "send_value" but that write a "/" on my lcd.

if someone could help me it would be great Smile

(sorry for my english, but i think you can understand Rolling Eyes )

DooD
Ttelmah
Guest
Re: Show a value on lcd, got a "/" :(
PostPosted: Mon Feb 02, 2004 4:38 pm     Reply with quote
quichedood wrote:
hi everybody,

i'm new to ccs, and i try to realize my project.
i've done some functions who works but i'm locked on something who looks very easy :p

so here a part of my code :

Code:

int temperature;
char mystring[21];

//send a char to lcd
void send_char(char str_eight){
   output_high(LCD_RS);
   trait_eight = align1(str_eight);
   OUTPUT_A (trait_eight);
   enable_lcd();

   trait_eight = align2(str_eight);
   OUTPUT_A (trait_eight);
   enable_lcd();
}

//Send a value to lcd
void send_value(int value){
   sprintf(mystring,"%u",value);
   send_char(mystring);
}

temperature = 65;
send_value(temperature);



ok so here is the problem the function "send_char" works fine
example : send_char("test"); -> "test" is writtent on my lcd

BUT, now i would like to show the content of "temperature" (who's 65)
so i use the other function : "send_value" but that write a "/" on my lcd.

if someone could help me it would be great Smile

(sorry for my english, but i think you can understand Rolling Eyes )

DooD

This is not a CCS problem, but a general 'C' one...
The function 'send_char', expects to receive a single character. It only works with the 'constant' string 'test', because CCS has a 'shortcut', that if a constant string is handed to a function expecting single characters, it will automatically call the function repeatedly to send the individual characters. When you call the function with 'mystring', the _address_ of the RAM string is handed to the function, which happens to display as a '/'...
You can work two different ways. The first is to write 'send_string' function, that takes the address, and steps through the characters one by one, till it sees the end of string ('/0') marker, so:

Code:

void send_string(char *str) {
    while (*str!='\0') send_char(*str++);
}

Then call this instead of send_char inside send_value.
or simply use printf, rather than sprintf (which supports sending the output to a function, rather than to a string), so:
Code:

//Send a value to lcd
void send_value(int value){
    printf(send_char,"%u",value);
}

You then don't need 'mystring' at all.

Best Wishes
quichedood



Joined: 02 Feb 2004
Posts: 5

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PostPosted: Tue Feb 03, 2004 2:53 pm     Reply with quote
thanks a lot for your reply ... but it doesn't work anyway :D
here is the code :

Code:
//Send a string to lcd
void send_string(char *str) {
    while (*str!='\0') {
          send_char(*str++);
    }
}

//Send a value to lcd
void send_value(int value) {
    printf([b]send_string[/b],"%u",value);
}



the text in bold is a little correction of what you give me (good isn't it ?)
so if anyone have an idea... I will look at it tonight, i'll keep you informed if something works Smile


EDIT : for value=65 it write "q q" on lcd if it can help someone Smile
(not real "q" that's the letter who correspond to this char code : 11100111)
http://home.iae.nl/users/pouweha/lcd/lcd.shtml

EDIT2 ( Confused ) : send_string function doen't work correctly (when using it without send_value function)
quichedood



Joined: 02 Feb 2004
Posts: 5

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PostPosted: Tue Feb 03, 2004 3:46 pm     Reply with quote
ok so here is my result :p

with that code :
Code:
//Envoi d'une chaine au lcd
void send_string(char *str) {
    while (*str!='\0') {
      send_char(*str++);
   }
}

//Envoi une valeure au lcd
void send_value(int value) {
    sprintf(mystring,"%u",value);
   send_string(mystring);
}


sending a value works great (thx !!!)
sending a string using send_char works
sending a string using send_string doesn't work

so why the last one doesn't work ? it should no ?
quichedood



Joined: 02 Feb 2004
Posts: 5

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PostPosted: Tue Feb 03, 2004 4:15 pm     Reply with quote
little screenshot Smile


but sending a string using send_string doesn't work better Laughing
Guest
PostPosted: Tue Feb 03, 2004 4:30 pm     Reply with quote
quichedood wrote:
ok so here is my result :p

with that code :
Code:
//Envoi d'une chaine au lcd
void send_string(char *str) {
    while (*str!='\0') {
      send_char(*str++);
   }
}

//Envoi une valeure au lcd
void send_value(int value) {
    sprintf(mystring,"%u",value);
   send_string(mystring);
}


sending a value works great (thx !!!)
sending a string using send_char works
sending a string using send_string doesn't work

so why the last one doesn't work ? it should no ?


You are misunderstanding what I posted.
The second example I gave, was an _alternative_ to the first.
You can just use:
Code:

//Send a value to lcd
void send_value(int value){
    printf(send_char,"%u",value);
}

The printf function, will call the function given as the first variable, for each character in turn. The 'send_string' routine, was designed to take a string input, if you needed/wanted to do it this way. The printf example would work as posted. Your 'modification', is _wrong_, because the 'send_string' function, expects to receive the _address_ of a string, while the function used by printf, is expected to receive a single character. You are repeating the same mistake...

Best Wishes
quichedood



Joined: 02 Feb 2004
Posts: 5

View user's profile Send private message

PostPosted: Wed Feb 04, 2004 2:50 pm     Reply with quote
oops sorry, i re-test like you said and all it's ok Very Happy
so thx a lot once more for the solution and all your explications !

i'll maybe come back later on this forum, very usefull Smile

see you later.

DooD
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