Hacking fx 7000 G
This is a very old calculator, but it has some interesting features, which are not present on other CASIO types. It has only 2 KB of RAM, but the address mirroring simulates 4KB RAM, where the higher 2 KB returns always 255 (0xFF).
Map of memory:
A[0] .. A[79] - user memory area, programs, etc.
A[80] .. A[175] - graphic memory buffer
A[176] .. A[191] - ?->X buffer (buffer for input while executing ?->X command)
A[192] .. A[207] - command buffer
A[208] .. A[233] - VIDEO RAM
A[234] .. A[254] - unknown :-(
A[255] - magic variable, similar to A[1024] on fx7700 GB, but it is not so magic.
I found only one feature - after entering 1.1->A[255] calculator switches off. This very usefull for me, because this calculator has a mechanic switch, which is not working in my case:-(.