Excuse my limited knowledge on this... For proprietary reasons I must split my 8051 code so I can supply one section to a vendor who will perform testing on the product. I broke the code into Banks but am having trouble with the calls. Both with SiLabs emulator and running without the emulator the program counter goes back to reset instead of reaching the banked functions. Details: I broke the code into two projects, built them with "unresolved externals" warnings - because the code isn't there. It is in the other bank. I use ohx51.exe and then "Hex2Bin /L131072 RP0.h00 Linked.bin" ...and... "Hex2Bin /O0x9c40 /M RP0.h01 Linked.bin" and finally bin2hex /4 Linked.bin Linked.hex. So the unit just sits there reseting over and over again. Any clue what I'm doing wrong? Replies are greatly appreciated! ALSO: I need to know if it is possible to pass parameters in Banked calls.