Konami SCC - More On Memory

More On Memory

The memory area from 9800h to 987Fh behaves as RAM as long as the deformation register is reset. The memory area from 9880h to 98FFh is write only; if you read it, it'll always return FFh. Watch out for reading from the deformation register, as this will set bit 6.

The memory area from 9900h to 99FFh has exactly the same function as from 9800h to 98FFh, 9900h through 99FFh and so on to 9F00h through 9FFFh. This happens because the SCC chip is not connected to address lines A8 through A10, so it cannot distinguish these ranges.