Hi Everyone, Where I work we are using a method of calibrating our units where we run some tests and then actually patch the correct value into a very specific location in the HEX file just before programming the unit. The way they kep= t these locations open was something like org 4 clrf PCLATH goto reset Calibration_Vector org 6 org 10 retlw 0 The hex file is generated based on this, and then the calibration values are inserted into the hex file in either program memory location 6, 7, 8, o= r 9. The value is actually the instruction retlw XXh with XXh being the value that we use to calibrate. Basically we jump to Calibration_Vector and then it returns and puts our value in W. Anyway, the question is not about how this works. The question is: When I assemble the code using MPLAB 7.20 I get a hexfile that appears to have optimized out those empty spaces. That makes the hex file's format different enough that our program (that has been in constant use for 7 years) doesn't find the correct place to insert the value. To mak= e the hex file's format match the old hex file (by match I simply mean has th= e same addresses listed in the 3rd through 6th bits of each line in the hex file, content can be different) I now have to insert NOPs between org 6 and org 10 to hold it open. Okay, here is the question for real... am I thinking about this correctly? Does anyone know for sure if this change I'm noticing does in fact correspond to the newer version of MPLAB? Are there any suggestions for fixing this in a way other than my insertion of NOPs method? Thanks for any help, James -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist