64DD

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The 64DD is a magnetic disk drive peripheral for the Nintendo 64 game console developed by Nintendo. It was announced in 1995, prior to the Nintendo 64's 1996 launch, and after numerous delays was released only in Japan on December 1, 1999. The "64" references both the Nintendo 64 console and the 64 MB storage capacity of the disks, and "DD" is short for "disk drive" or "dynamic drive". The 64DD was codenamed "Leo" during development.

Physical Memory Map

The following is the physical memory map for the 64DD hardware:

Address Range Name Description
0x05000000 0x050003FF ASIC_C2_BUFF C2 Sector Buffer
0x05000400 0x050004FF ASIC_SECTOR_BUFF User Sector Buffer
0x05000500 0x0500057F Registers 64DD interface
0x05000580 0x050005BF MSEQ_RAM_ADDR Micro Sequencer RAM
0x06000000 0x063FFFFF DDROM 64DD IPL ROM

It is usually accessed under the KSEG1 memory segment as uncached direct access to those registers.

64DD interface

The 64DD interface is made of several 16-bit memory-mapped registers allowing the CPU to control the 64DD hardware.

64DD commands

One of the main use of the 64DD is through commands. Commands are a single byte, with sometimes a 16-bit argument passed as data.