Format of TI73 files By Timothy Joseph email: tim@timsplace.org URL: www.timsplace.org Please anyone who can help me please do!!! I would like to get TI73 files so that I could study them considering that I don't have a TI73 and graphlink software won't work on my computer. :( If you would like to help, then drop me an email to the address below. ti73@timsplace.org I would be glad if someone could help. Thanks! Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Format of TI73 files Program Files The format in which the TI73 file formats are are still questionable. But so far this is what I have "learned" by Hex-Editing a few TI73 programs... -------------- Contents of the bytes of the file... Bytes; Decimal Contents -------------------------------- 00-10 **TI73**... 11-?? Comment 59 05,06 63-67 Program Name 68-XX The Program Itself??? Last two bytes indicate the checksum. -------------------------------- About bytes 00-10 All files begin with byte zero. So let me get that straight. Now, the first ELEVEN bytes within the file indicates what type of file it is. This file is a TI73 file, indicated by, "**TI73**..." In order to emulate a program like this, you will need to change the last three bytes (8-10) to 1A 0A 00. That way when you use the TI-Graphlink software, you will not get any complaints telling you that the file is "BAD." Should be simple to understand. If you intend to change any of the bytes you will need to update the checksum of the file. The checksum of the file can be found at the last two bytes of the file. I'm not sure if the checksum is saved as Low byte first then high byte (like the TI82), or if it is high byte first and low byte second. About bytes 11-?? This area is where comments of the file are kept. I'm not very sure if the comment continues to byte 58 and stops. Meaning:There may be something else stored other than a comment in that area. I'll work with it a while. About byte 59 Byte fifty-nine determines whether the program is protected or if it is unprotected. If the program was created on the clalculator, then byte fifty-nine will be '05'. Unless the file is protected by using the Graphlink software to protect the program. If the program is protected, Meaning: You cannot edit the file from the EDIT menu of your TI73. Then byte fifty-nine will be '06'. About bytes 63-67 Bytes 63-67 give the program name. Regardless if the program name is only one byte. The file (while on the computer) will be eight bytes long. If the program name is only one byte long. The next seven bytes will be '00'. About bytes 68-XX I'm not sure what comes after byte 67. There could be more things other than the program??? I'd have to look at the file through TI-Graphlink software to find out. But I don't have a TI73. :) But for the rest of the file, it is the program itself. About the last two bytes The last two byted indicate the checksum of the file. The checksum of a file is when you add up all the bytes of the file. That total number is the checksum. If for any reason the checksum goes over FFFF on the TI73. The checksum will roll over to 0000 automatically and continue to count the bytes. But remember, this is not official but is a "theory." I will study the checksum of the TI73 file. End of file so far...