I looking for a file to convert from asm to hex file so I can load to the eeprom programmer. Right now I use the A51 with emp20 but I want to use the Willem Universal programmer.Because the Willem Programmer just take hex, bin,...other than .asm. I heard that bl51.exe can handle it but I don't know how to get it.
BL51 is part of the Keil toolchain. Are you certain that the A51 (or whatever) you are using is part of a Keil product?
http://www.keil.com/c51/a51kit.asp