Here is some documents I have scanned from manuals and gathered from internet. All copyrights of these documents goes to original holders. I am providing just download mirror because some of these documents are difficult to find, and some can’t be found from internet at all.
I scanned and cleaned following manuals that came with the X-07:
Canon X-07 Basic reference manual
Canon X-07 Programming for beginners
I was also able to source these files from internet:
Schematics of CPU board, LCD & keyboard and memory subsystem.
From schematics you can see X-07 could address much larger memory than 24kB. Theoretically 16Bit addressbus allows to access 216 × 1 byte = 64 kilobytes of memory. Memory is split in different banks by address decoder ICs. Part of it is of course taken by BASIC interpreter ROMs. 24kB ram is addressable between 0000 and 5FFF. Addresses 8000 to AFFF are reserved for optional TV adapter that has its own video RAM, control ROM and BASIC expansion ROM. This area could be theoretically used by other devices.
RAM card address space could be transferred to RAM socket, as 2000-3FFF is reserved for it. With 16K RAM chip or two 8K ram chips soldered together RAMPA line can be connected to second Chip Enable line of RAM IC’s, this line controls CE pin of RAM card. Lifting RAM pins 1 (A14) and 26 (A13) from sockets gives two address lines to ram that can be connected to address decoder IC’s, giving access to 16K or 32K part of 28pin RAM package.
Own ROM/Flash expansion could be wired like that to enable own permanent assembly programs. Interestingly flash chip could also be wired as ram giving non-volatile storage for saved BASIC programs.
Interestingly RS232 port is buffered to 0-5V range, so it isn’t true rs232. Also there is TXD and LTXD lines, LTXD being connected to HD61L202 LEO pin.
There are some french books about assembly programing with X-07. Copies are provided here
There aren’t much more documentation available on internet about Canon X-07. It was not that popular in England, but saw some popularity in France at computer clubs.