Jumper,

Thanks for the insights.

I'm a VB6 sorta guy and I have the complete MS Visual Studio, so that's what I'll do the application in.

My previous comments about parsing the .hex file lines and padding the short ones might have been premature. I was thinking about how you'd implement this if the PIC was coded in assembler, in which case I believe you generally write 64 byte blocks. In that case, the file lines would have to be read, buffered, parsed, and disassembled & reassembled into the 64 byte chunks the PIC likes to work with before transmitting to the PIC. I still haven't figured out all the limitations of WRITECODE, but it seems to me that, assuming the intended write block has been ERASECODE'd, you can write one byte at a time? In this case, it's quite simple as you said, and data can be fed to the loader in chunks as small or big as it can buffer in RAM. Do you agree??

Joe