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#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
"is it receiving all the characters? or it is receiving all characters and me not able do display it on lcd?"
That really is something for you to determine in your own debugging of your system!
you presist in throwing the whole thing together and asking "what is wrong"
DIVIDE AND CONQUER!
Erik
#include <reg51.h> #include <string.h> #include "lcd.h" #define INPUT_LENGTH 12 #define ACCEPTABLE_INPUT_COUNT 2 char getCharacter(void); int input_pos=0; char input[INPUT_LENGTH]; int main() { int i,j; /* Array of data that this programs thinks is acceptable */ char acceptable_inputs[ACCEPTABLE_INPUT_COUNT][INPUT_LENGTH] = { "$0016221826", "$0016234114"}; lcd_init(); lcd_clear(); SCON = 0x50; TMOD = 0x20; /* timer 1, mode 2, 8-bit reload */ TH1 = 0xFD; /* reload value for 2400 baud */ TR1 = 1; while(1) { input[input_pos++] = getCharacter(); if(input_pos==11) { for (i = 0; i < ACCEPTABLE_INPUT_COUNT; i++) { j = strcmp(acceptable_inputs[i],input); if(j==0) { lcd_printxy(1,8,"yes"); input_pos=0; } else { lcd_printxy(1,1,"no"); input_pos=0; } } } } } char getCharacter (void) { char chr; /* variable to hold the new character */ while (RI != 1) ; chr = SBUF; RI = 0; return(chr); }
when i debug step wise its working properly. when i download it to the microcontroller and give input i.e rfreader will read the ID number and sends it to MCU, the o/p is no, and again when i try to download for the next time i,e as soon as i click on "start" to download the program, output will be yes. Please help me to resolve this
Sorry, but no. You haven't debugged your code. It does not work when you step through it either.
You don't need to step through in a debugger - enough to follow the flow with pen and paper and try three different alternatives. Code matching first acceptable key. Code matching second acceptable key. Code not matching any key.
for (i = 0; i < ACCEPTABLE_INPUT_COUNT; i++) { j = strcmp(acceptable_inputs[i],input); if (j==0) { lcd_printxy(1,8,"yes"); input_pos=0; } else { lcd_printxy(1,1,"no"); input_pos=0; } }
How did you decide that if your input fails the test against the first code, it's a failure? Don't you think you need to iterate through the full array and first when all known codes mismatches, it's a fail?
Did't you notice that when you did your stepping through the code?
Why are you in such a hurry? The logic is simple. But to get something to work, you need to have the patience to work out all acceptable and unacceptable paths and verify that they they happen as expected. Any time you take a shortcut, you cut yourself. It is costing _you_ a lot of time, that you don't work a bit slower and really try to follow the logic of your code.
for (i = 0; i < ACCEPTABLE_INPUT_COUNT; i++) { j = strcmp(acceptable_inputs[i],input); if(j==0) break; } if (j==0) { lcd_printxy(1,8,"yes"); input_pos=0; } else { lcd_printxy(1,1,"no"); input_pos=0; }
as you said i am getting problem in this part of code. it is receiving all the characters but not able to compare, it is printing "no" on the lcd.. i am not able find out why it is happening so, Sir please help me out. which step of the above code should be corrected.
@Andrew Neil
Why don't you write a bit of the code at a time and test it before doing the next bit. You stand a chance of creating a whole project that works properly.
I thought the strings from the RFID reader ended with a newline. If so - how do you handle the line breaks?
And what is the result of your debugging? Soon one month later. Own time debugging the individual parts of the program would have made you finish this project about three weeks ago. Of course, that would have required you to take regular looks in a book about the C language, when the debugger showed you that a statement didn't do what you thought it would do.
Own time debugging the individual parts of the program ... take regular looks in a book about the C language if you need to do that then what are fora for?
Of course, I AM being Ironic.
Pradeep,
Let's try taking a step back. When you create code, how do you normally test it or decide that it is working? Do you look over it and evaluate if it's correct or not? Do you press the simulate button and step through the program, watching how the code handles each statement? Do you program it directly to the chip and observe the results?
I think what everyone here is trying to help you with is not just how to solve the problem with THIS code but to teach you how to solve code problems without needing a forum to come to with each issue. The more familiar you are with the tools, the more you will be able to determine WHERE the problems are in your code. Maybe you won't be able to solve everything on your own right away but it should help you come back to the forums with the problem area of the code (without posting ALL the code) and give more information about what the problem is (rather than "I have a problem, please help").
So, at this point, can you describe how it is that you evaluate whether your code is working?
i am very sure that when i debug i am getting the output but when i download it and read the input using rf-reader its is not comparing. i even tested the rfreader on the hyper-terminal it is reading the correct values.. so the problem might be that i may be receiving some converted values like hexadecimal or octal digits that i dont know... but i am sure that i am not receiving the decimal digits in to the SBUF..
what will be the output of rs232? will it be in the form of hexadecimal or decimal? because i have displayed the no which i am receiving.. what i have done is i gave the input through flash magic(flash magic-tool-terminal). for 'a' i am getting the display as 02, for p i am getting the display as 128 etc ... i not getting what these no's are?
try to understand my problem and help me out
There are no binary, octal, decimal or hexadecimal values - there are just values. Octal is a way of _presenting_ a number. But the value 123 is still the value 123 even if you decide to express it as 7b hex or 173 octal or 1111011 binary.
When will you take care of the newline characters that I have mentioned to you several times?
The output of RS232 is a series of positive and negative voltage levels; in that sense, it is "binary" - meaning, "a system that can take one of two values at any one time"...
www.lmgtfy.com
do i need to convert the binary no received in SBUF to decimal or ASCII and then i should compare with the other no?
But I just told you the processor have no binary or decimal or octal or hexadecimal.
A number is a number. Binary just means that the number is presented in base 2. Hexadecimal means the number is presented in base 16. But the number 17 is still the number 17.
If your device sends the codes as a sequence of ASCII characters and your hard-coded keys area also sequences of ASCII characters, then you obviously don't need any conversion. If you decide to try to store the keys as numbers (bad, since they can be larger than what you can store in a long int), and the connected device sends in codes as ASCII then you will obviously have to convert the stored numbers into ASCII strings or convert received ASCII data into numbers. But your examples suggests that your keys are already arrays of ASCII digits and the UART receives sequences of ASCII characters.
How long are you going to ignore my question of when you plan to implement synchronization with newline characters, since your code currently just count received characters and assumes that they represent a key code. And your code ignore the off-by-one between each code, when you receive a newline character and most probably considers it to be the first character in the next key...
Problems seldom go away just because you ignore them.
'maybe' is the only possible answer
the "debugging method" of throwing some code together and posting it on a forum is not very efficient and will, probably, never get you to ways end
If you had even an inkling of what you had coded for you would not ask the above question.
do some REAL debugging (if you are even able to do so) and post the results, do not just keep posting irrelevant questions