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 2008-12-01T23:02:34-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t10306.html 2008-12-01T23:02:34-08:00 i been given assignment relating to 8051 microcontroller . how ever , i got some problem when interfacing 8051 with a high to low voltage shifter (74HC4050) . i nid to feed a input from 8051(5V) into a SD memory card which only receive maximum voltage of 3.3V . anyone know how to interface ?can i just direct connect the output from 8051 to 74HC4050 then from tat into SD ? how i ensure tat the output voltage from 74HC4050 wil drop from 5V to 3.3v at least ? thank you http://www.8051projects.net/forum-t10306.html 2008-12-01T23:02:34-08:00 Ajay just connect 5V test signal to 74HC4050 and see if you are getting 3.3V at the o/p.make sure that 74HC4050 is not bi directional so you might have problem when reading from SD Card.