I have written a code for getting input from ADC 0804 and then display the value on 16x2 lcd I need help in writing a function to convert ADC output into a value which can be displayed in 16x2 lcd. ADC is used to convert temperature output from lm35. 5V supply voltage and Vref=2.5V. I need code for - convert_display(value) Also keil compiler gives error - adc_inter.c(16): error C141: syntax error near '='. I am unable to understand what should be done?
#include <reg51.h> #include <stdio.h> #include <string.h> void msdelay(unsigned int time); void convert_display(unsigned char value); #define RD P2^5; #define WR P2^6; #define INTR P2^7; unsigned long MYDATA;
void main() { unsigned char value; MYDATA = P1; MYDATA = 0xFF; INTR = 1; RD = 1; WR = 1; while(1) { WR=0; WR=1; while(INTR==1) { } RD=0; value=MYDATA; convert_display(value); RD=1; } }
void msdelay(unsigned int time) { unsigned char x,y; for(x=0;x<=time;x++) for(y=0;y<=1275;y++); }
Think twice about this statement. sprintf() can now either make a number into writable characters (ASCII) or into binary, hex etc? Next thing - what numerical bases can sprintf() use when translating a number into a sequence of ASCII characters?
Peter:
obviously sprintf converts to ascii. What I meant, was that it will convert your number into an equivalent ascii number. %o gives you octal %x gives you hex
I have worked with a version that had a %b and would give you the result in ascii binary i.e. 0x31 0x30 0x31 0x31 0x30 for 10110b That is not part of the standard library
if you do "%h",value you get base 16 or hex %o base 8 or octal %c base 256 when you think about it :) %u base 10
or is it base-128 ... ?
Base 128 if you are a 7 bit character. 256 if you are an 8 bit character. 00-0xFF. Technically it has to be 256 because the definition of a base requires the number to reset to 0 when you get to the end of the range 0-0xf then 0 0x7F +1 0x80, so if you are looking at it as a 7 bit word, and you mask the upper one off, then it would be base 128.
Actually I don't know *what* sprintf would do if you gave it a 16 bit number. It might use the upper byte on one endian machine or the lower byte on a different endian machine, or it might just spit it's guts all over you at compile time, if you did your prototyping right.
I wish the C guys had seen fit to adopt my quad for long long, but way back it got nixed. I still think quad would be a good one for a 64 bit variable.
Base 128 would imply that a 8-bit character larger than 127 would represent a printout of two ASCII characters - the high bit isn't allowed to just be masked away when talking about base-n numeric operations.
About printf() and 16-bit values - the language standard does cover multi-character character constants, but as implementation-defined.
I have a bit bad access to standard documents right now, but the old ISO 9899 standard (C99) has the following note (§6.4.4.4, bullet 10): "The value of an integer character constant containing more than one character (e.g., 'ab'), or containing a character or escape sequence that does not map to a single-byte execution character, is implementation-defined."
And J.3.4 covers implementation-specific behavior relating to characters: "The value of an integer character constant containing more than one character or containing a character or escape sequence that does not map to a single-byte execution character (6.4.4.4).
Character constants containing multiple characters are also a common cause for compilation warnings, because of the portability issues.