http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2009-01-08T04:57:02-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 I am facing a very strange problem with string length in my program. I am getting following compiler error with Keil compiler:*** ERROR L107: ADDRESS SPACE OVERFLOW SPACE: DATA SEGMENT: _DATA_GROUP_ LENGTH: 002EHProgram Size: data=111.2 xdata=0 code=2709The problem occurs if I take the size of string more than 40 i.e. char str[50]But if I reduce the size of string to 40 or less than 40 then code compile without any error.Please help me I need a string of around 160 length so that I can send an SMS using that string. http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 sashijoseph Yup...an idata variable should work.It allows you to use all of the 256 bytes. http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 pdi33 hi say2paul,maybe the problem is because the string is occupying the valuable RAM space( which is only 128 bytes in case of 8051). If the string is a fixed value ( u r not modifying the content in the program), try changing it to the following:constant char str[50] this will ensure that the string is stored in the program memory space instead of occupying the data RAM. http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 say2paul pdi33 wrote ...hi say2paul,maybe the problem is because the string is occupying the valuable RAM space( which is only 128 bytes in case of 8051). If the string is a fixed value ( u r not modifying the content in the program), try changing it to the following:constant char str[50] this will ensure that the string is stored in the program memory space instead of occupying the data RAM.I cannot take it as constant as I need to append data to same string..I think idata can work in this case as I am using AT89C55WD with 256 bytes of RAM. http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 say2paul Can I use AT24C08 (external memory) instead?? http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 say2paul Anybody . . ! http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 Ajay 128 bytes of memory of 8052 architecture is accessible directly using variables stored in ram, rest of 128 can only be accessed using indirect addressing.as sashi said try using idata (use the indirect part of your controller ram)e.g.CODE:
unsigned char idata abc[50];
 also if you want to use the external memory, its good but i would say a hectic process as reading and writing from eeprom is slow.try giving idata a chance http://www.8051projects.net/forum-t11326.html 2009-01-08T04:57:02-08:00 pdi33 hi say to paul,As so truely said by ajay, EEPROM programming is slow but if u are planning to use 160 bytes for ur application ,then the uC will have only 96 bytes for all the other processing including the stack. So i feel u should keep the other global variables and static variables to a minimum. Try using local variables (variables inside functions) wherever possible so that the same RAM can be reused by the uC for multiple functions making the code more efficient.good luck.