#include<reg51.h> void boud_rate() { SCON = 0x50; TMOD = 0x20; /* timer 1, mode 2, 8-bit reload */ TH1 = 0xFD; /* reload value for 2400 baud */ TR1 = 1; TI = 1; } char serial_receive() { char chr; /* variable to hold the new character */ while (RI != 1) {;} chr = SBUF; RI = 0; return(chr); } void main(void) { boud_rate(); unsigned char rx_data; for(;;) { rx_data = serial_receive(); switch(rx_data) { // case '1': open_door(); case 0067892341 : open_door(); break; // case '9': open_door(); case 0045780034 : open_door(); break; default: dont_open(); } proper_delay(); } }
errors
'rx_data':undefined identifier illigal octal digit
please tell me how to overcum these errors
So #include<reg51.h> inside main()?
And void boud_rate() inside main()?
And then a second main()?
Do you always do your copy/paste without checking what the result is?
I am very sorry for the mistake, plz help me to solve the errors. here in the program I am using decimal no no starting with zero, but it is taking as a octal digit. how to make it as a decimal?
#include<reg51.h> void baud_rate() { SCON = 0x50; TMOD = 0x20; /* timer 1, mode 2, 8-bit reload */ TH1 = 0xFD; /* reload value for 2400 baud */ TR1 = 1; TI = 1; } char serial_receive() { char chr; /* variable to hold the new character */ while (RI != 1) {;} chr = SBUF; RI = 0; return(chr); } void main(void) { baud_rate(); unsigned char rx_data; for(;;) { rx_data = serial_receive(); switch(rx_data) { case 0067892341 : open_door(); break; case 0045780034 : open_door(); break; . . . . default: dont_open(); } proper_delay(); } } errors rx_data:undefined identifier illigal octal digit
If you are going to pay someone $100 - do you then specifically write $00100?
If the compiler takes these numbers as octal - have you then taken a look at the language definition (lots and lots of books are available if you haven't access to the languge standard) to see how you in C define decimal, octal or hexadecimal numbers? Any book at least decent about describing the C language would tell you that 0x or 0X is the start of a hexadecimal number, and 0 (but not followed by X or x) is the start of an octal number.
Note that 10-digit decimal numbers spans 0 to 9,999,999,999. Do you think your C51 compiler supports that numeric range? So maybe you should consider using C strings and perform comparisons with strcmp() instead? You will not be able to use a switch statement, but at least you don't need to worry about the number of digits in each code compared to the numeric ranges supported by the target processor.
Another thing - with string comparison based on an array of known codes, you can break out your valid codes from the source code. With a switch statement, you do need to modify that switch statement whenever you need to change, add or remove a code.
OK, I'll lead you by the nose.
the reason that you are getting the rx_data: undefined identifier is that you are defining the variable after the call to baud_rate(). you can't define a variable after code in a code block.
your case statement is not going to work. rx_data is a single character, not a string of characters. You need to receive a number of characters, put them into an array, and then compare that array to your keys. a switch statement will not work for the array comparison.
Most of all, you need to pick up your C textbook.
OK, I'll lead you by the nose
did it hurt when you put the ring in?
... is that he REFUSES to read a C book before "writing" 'C'. His posts smell highly of "writing" 'C' after "studying" a couple of 'C' programs.
answer his most basic questions and he will be back tomorrow with "what is up on a resistor?"
I DO believe in helping posters, but the OPs questions show a fundamental lack of understanding the most basic aspects of programming.
Erik
thank you, completed the coding. . 250 numbers i have taken it in 2D array. and received no is another array and compared both using 2 for loops.
If you zero-terminate the character arrays or have a one-dimensional array of strings, you could make use of strcmp() instead of your inner loop.
Another thing is that it is normally nicer to maintain code containing a one-dimensional array (vector) of strings, than to have a twodimensional array of characters.
Did you make sure to properly tag your array to get it stored in CODE?
do i have to use < pre > and < /pre > in my c code? when i dont use them i get syntax error at line 32. i tried to Please read the manual but no find it. is it in the manual?
One idea here could be to attempt something like "storing variable in code site:http://www.keil.com" using Google.
oh woe, oh woe
< pre > and < /pre > are formatting codes for THE FORUM, they are not 'C"
line 32 tell us nothing, we do not have your code, and if we did do not expect us to go 1, 2, 3, .... 32
All the problems in this thread can be effectively and completely resolved with a functioning brain.
Yes - the most important tool in software development is the one between the ears!
void serial_int (void) interrupt 4 { static char chr = '\0'; /* character buffer */ if (RI == 1) /* it was a receive interrupt */ { chr = SBUF; /* read the character into our local buffer */ RI = 0; /* clear the received interrupt flag */ TI = 1; /* signal that there's a new character to send */ } else if (TI == 1) /* otherwise, assume it was a transmit interrupt */ { TI = 0; /* clear the transmit interrupt flag */ if (chr != '\0') /* if there's something in the local buffer... */ { if (chr == '\r') chr = '\n'; /* convert to */ SBUF = chr; /* put the character into thetransmit buffer */ chr = '\0'; } } } int main() { unsigned char a[5][11]={{0,0,0,1,6,2,2,1,8,2,6},{0,2,3,1,5,6,7,3,6,4,5},{0,0,1,8,9,6,7,6,4,2,3},{0,2,5,8,9,6,4,7,2,3,0},{0,6,4,3,7,8,0,2,5,3,7}}; unsigned char c[10],i,j; char chr; lcd_init(); SCON = 0x50; /* mode 1, 8-bit uart, enable receiver */ TMOD = 0x20; /* timer 1, mode 2, 8-bit reload */ TH1 = 0xFD; /* reload value for 2400 baud */ ET0 = 0; /* we don't want this timer to make interrupts */ TR1 = 1; /* start the timer */ TI = 1; /* clear the buffer */ ES = 1; /* allow serial interrupts */ EA = 1; /* enable interrupts */ lcd_command(0x10); lcd_prinit(chr); c[10]=chr; for(j=0;j<5;j++) { i=1; if(a[j][i]==c[i]) { for(i=1;i<9;i++) { if(a[j][i]!=c[i]) break; } if(i==10) { // opn_dor=1; lcd_printxy(2,1,"yes"); } } // opn_dor=0; lcd_printxy(2,1,"NO"); } }
there are no errors and according to me the logic is correct... but still not getting the output(display-yes or no) please help me me not able to get the characters which are received in the interrupt program
So, are you _really_ sure your code is correct?
unsigned char c[10]; <= 10 elements
c[10]=chr; <= assigning to the 11th, element...
i=1; <= ignoring first character (zero) and start with second character (index 1). if(a[j][i]==c[i])
for(i=1;i<9;i++) { ... } if (i==10) { ... } <= how would i reach the value 10, when the loop ends if i reaches 9?
lcd_printxy(2,1,"NO"); <= printing "NO" even if you just printed "yes".
So - exactly how much did you verify your code? What was the result of the debugging? Did you really step through the code and check the values of the variables and how the execution jumped? Or did you just _assume_ what it would do?
Next thing - guess how much simpler your code would have been if you had stored the keys as strings:
char key[] = "00016221826"; char input_key[12] = ""; ... if (!strcmp(input_key,key)) { lcd_printxy(2,1,"yes"); }
Any special reason why you decided to ignore the suggestion to look at strcmp()?
By the way - when will you take care of the use of the "chr" variable?
You have one such variable in your interrupt handler. You seem to attempt some broken variant of echo.
You have another variable with same name (but totally different variable) in main(). But you never fill the 10 - or 11 - slots of your c[] array. So what will you then compare with the stored keys?
Wouldn't it be better if c[] was global, and the interrupt checked if the array was available or not? If available, then the interrupt handler adds a character at a time until you get the newline. If you get newline after exactly 11 digits, you set a flag that main() can process. And your interrupt needs to ignore all new characters received until main() is done. If you get the newline too early, then you failed somewhere and have to reset counter and start getting 11 new digits. If you get a 12th digit, then you also fail and have to wait for a newline to regain sync.
Same algorithm if using strings - but then you have to add yet another character ('\0') when you have all digits, to terminate the string.