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 2009-01-07T21:41:31-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t7412.html 2009-01-07T21:41:31-08:00 Hello!I've got problems with programming an AT89S2051. I'm using a programmer called ATMEL ISP from Ulrich Bangert (that's the link: http://ulrich-bangert.de/ATMELISP.zip). It's an really easy to build programmer, because it only uses an RS232 to TTL/CMOS converter and a 74HC126.I've built it and it functions, because I'm able to program an AT89S8253 with it. But I'm not able to program an AT89S2051 or to read out the code memory of it. Sometimes when I try to program the 2051 all ports are LO (also after reset), but the most time nothing happens.Can you help me? Why is the 2051 making problems? http://www.8051projects.net/forum-t7412.html 2009-01-07T21:41:31-08:00 Ajay AT89S2051 is not supported by atmel ISP. Please try not to program it.. you may get your IC burnt. http://www.8051projects.net/forum-t7412.html 2009-01-07T21:41:31-08:00 elfcurry I think netx1 is right, Ajay.The S in the part number AT89S2051 means it can be serially programmed in the target system. I have such a part and ISP programmer and will soon try it. Maybe I've misunderstood you but surely Atmel's AT89S parts use the same algorithm? http://www.8051projects.net/forum-t7412.html 2009-01-07T21:41:31-08:00 Arun Kumar V Maybe I've misunderstood you but surely Atmel's AT89S parts use the same algorithm?that need not be, AT89S51/52 share common algorithm but At89S53 has 4 bit (nibble) algorithm and also At89C55 is different to At89C55WD when it comes to programming.best advice would be to read the Device datasheet and decide accordinglyArun