3-5 Accessing the Disk


64DD related instructions are designed on the assumption that another PI device is not being accessed. For this reason, a system using the 64DD should not access the disk and another PI device at the same time. The same thing applies to the use of font data and wave data. Therefore, you must come up with some work-around, such as accessing the disk after you have read the necessary data into a buffer. One way to prevent simultaneous access of the disk and another PI device is to create the program so that instructions to the disk and the ROM cartridge are managed with a single thread, and processes are performed while messages are checked.

PI device : Mask ROM, SRAM, etc.