A83: Converting TI-83+ Flash ROM upgrade to binary


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A83: Converting TI-83+ Flash ROM upgrade to binary




The new version of Virtual TI supports TI-83+ emulation, so I tried using
TI's Flash ROM upgrade file (base112.hex), until I realized it was in hex
and wouldn't work. So I wrote a program to convert it to binary, and filled
the file with 0's until the length was 256*1024 bytes. Then, VTI would
recognize it, and display it in the list of ROMs as TI-83 Plus version 1.12,
but it won't run; VTI just displays a blank TI-83+ screen and appears to
freeze.

To convert the hex file to binary, my program read the Base112.hex file and
processed all the lines of length 75 (it skipped over the rest), then
skipped the first 9 bytes of each of those lines so there were 66 bytes to
process, and then converted each dual-byte hex code to a single binary byte
and placed it in the binary file. Only 236742 bytes were filled that way, so
I filled with 0's up to 262144. Obviously the encoding method is more
complex than the above; it appears that the first 9 bytes of each line
indicate perhaps the location of the hex string in the assembled ROM, but my
program just assumed all the lines were in order, which they probably
weren't. However, I did find calculator text inside the binary file I
created (such as various TI-83 commands), so I know the file isn't
encrypted.

So, is there an easy way, or an already available conversion program, to
convert the TI's 83 hex ROM file to binary format so VTI can use it?




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