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 2009-01-08T07:24:06-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 i have read more about this avr ..but i had still problem with my SPI. can you explain about this.. i was tested data from master to slave and slave to master.. the data received by the slave to be correct.but data received by the master from slave is different.. and also explain about the .db ..how can i store the values in rom.. http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 Ajay db is an assembler directive tells assembler to store data in byte manner. to use it.. you can either give bytes to be stored in hex format separated by commas or if its a string then it will be enclosed by double quotes.. here is an example...db 0x10, 0x30, 0x45.db "this is an example"thats all.. if you want to store them in a specific location.. then.org $100.db "this will be stored at 100H" http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 MATHIVANAN thanks.. but how can i recall the data from .db (assembler directive). and also explain about my SPI PROBLEM http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 Ajay please take a look at the AVR tutorials in the Ebooks and Tutorial forum to know how to read from ROM. In brief you need to use LPM instruction.Regarding your SPI, i didn't get what you are trying to say.. Can you please be more specific with data sent from slave is different!!? which SPI device you are trying to read from? http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 MATHIVANAN hi ajayi am sending the data from atmega8515 and also again get the data from atmega8515 through SPI http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 Ajay you mean you are looping back? or you are sending from one ATmega8515 to another? http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 MATHIVANAN sure..i got the solution and also i communicate one slave with two master.. i got all solution but i not got solution about RTC? http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 MATHIVANAN i need to learn embedded c. can you guide me or suggest good book http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 zeeshan99s any help in C ? http://www.8051projects.net/forum-t2543.html 2009-01-08T07:24:06-08:00 zeeshan99s i dont know one for bigAVR but if u jst want to know a book for concepts go for8051 micro controller by scott mcanzee .. any one who can guide me how to program SD/MMC card using bigAVR atmega 128, & the compiler is codevision ..i tried the sample program which is written for WINAVR . i runs perfect without an error but i dont know how to configure it , the comments are there but language problem