LPC2378 ISP file format

Started by bausin, May 05, 2008, 09:52:50 AM

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bausin

Hi,

I have a general question about the file format used as input by FlashMagic.
The user's manual says the input file should be uuencoded, but FM says to
specify an Intel Hex file. What am I missing?

Thanks,
Steve

Paul Claessen

You're missing nothing!
FM takes as input an Intel Hex file.
It (FM) will then generate the necessary ASCII commands and convert the data to Uuencoded data.

bausin

Paul,

Thanks for the reply. Just seems strange that NXP wants the data uuencoded when Intel hex is already "ascii-ized".

Steve

Paul Claessen

Steve,

Intel hex and uuencode is not a 1 to 1 relation: Only the actual 'data' that is to be flashed should be uuencoded. An Intel Hex file contains more than just 'data' that is to be flashed. It also contains location information, start address information, and checksum information. From this, FM generates ASCII commands that do all the erasing, reading and writing.
So, only PARTS of the hex file are being converted to uuencode.
The reason NXP wants uuencoded data is that it is more compact than hex encoded (3 8-bit binary bytes map to 4 ASCII bytes, rather than 6 ASCII bytes in hex).

bausin

Paul,

So FM recombines the two "ASCII" data bytes in the hex file back into one binary byte and then uuencodes it. I was thinking FM uuencoded each ASCII byte in the hex file which would be really inefficient. This makes more sense.

Thanks,
Steve