Getting char from computer and type it on GLCD (problem)

[Abdulla M.A.]

Hi guys,
when I execute the program and start typing letters, nothing appear
on the GLCD, why???

[Wayne_]

I have not used that driver but looking at your code :-

glcd_text57(xt,yt,text,1,on);

it looks like glcd_text57 requires a string, text is a single char. This probably means the next location in memory does not contain a null.
Your program will output garbage.

Either use a put routine to output a single char or convert the char to a string.

[Abdulla M.A.]

I get the input as a string, I stored it in text array, nothing changed!!
gets(text);
glcd_text57(xt,yt,text[i],1,on);

I think glcd_text57 deal with char. because "Hello" message appeared on
the glcd. but the char. sent from computer did not appear on glcd.

Abdulla
_________________
"A scientist can discover a new star, but he cannot make one. He would have to ask an engineer to do that."
"For an optimist the glass is half full, for a pessimist it's half empty, and for an engineer is twice bigger than necessary."

[Wayne_]

I just checked and glcd_text57 does require a string.

unsigned char text45[6]={"Hello"};
"Hello" is a null terminated string.

unsigned char i,text;

text is a single char.

gets(text); will wait for a STRING to be entered, you must press enter key. If you havn't change the definition of text your program will most likely fail.

You have 2 options.

option 1 if you want to enter a string by typing the full string out and then press return

[Abdulla M.A.]

Correct this.
text[1] = '\0'; // null terminate my single char making it a string
now, the program work fine.

if I just want to get the xt and yt from computer, I assumed I should
add the following

unsigned int32 xt, yt; //

gets(xt);
gets(yt);

I added it but, the program worked fine if xt, or yt contain just one
number like (4,6), if xt=16, and yt=30 the program did not work
correctly, why?? int32 is 32 bit, so I think I can fill it with four numbers!


I'm really grateful for your help Wayne_ , thank you.

Abdulla
_________________
"A scientist can discover a new star, but he cannot make one. He would have to ask an engineer to do that."
"For an optimist the glass is half full, for a pessimist it's half empty, and for an engineer is twice bigger than necessary."

[Wayne_]

Several problems.

First:- gets expects a string of characters and expects to store the data into an array of 8 bit values (chars). Your code should fail as you are trying to read a string in to an int32.

Second problem is how you are sending the data from the PC. If you are using a program like hyperterm then the PC will be sending ASCII characters. The value 1234 will be characters '1', '2', '3' and '4' not the decimal values. if you are sending bytes, then you could send the value 1 followed by the value 2 etc but you still have a problem as shown next.

Third problem is that a 32 bit int can hold a value up to 4294967295. The computer can at most send bytes, even a 16 bit value would be split in to 2 bytes. You need to receive these in to a buffer and then convert it to an int32 when all numbers have been entered.

If you have a program to send the data then you may be sending 4 bytes for a 32bit value, again you would need to receive these one at a time and convert, transpose in to your 32bit var.

Try searching the forum on how you can do this.