X68000

The MSM6258 was made by OKI and is used inside the Sharp X68000 or (I think) the NEC PC-FX. It is a 1-channel ADPCM Chip with a build-in DAC. It was later superseded by the MSM6388 and the MSM6588, which include a higher quality DAC (12-bit instead of 10) and a Low Pass Filter.

Akumajou Dracula used the MSM6258 to play the Drums on the X68000

Technical Specifications

• Channels: 1
• Channel 1: 3-bit / 4-bit ADPCM Sample Playback
• Sample Frequency: Supports 15.6 kHz, 10.4 kHz, 7.8 kHz, 5.2 kHz and 3.9 kHz
• Stereo: No (its 1 channel after all)
• DAC: build-in, 10-bit
• RAM: External, could be DRAM, SRAM, ROM or an EPROM.
• The Chip also outputs a (digital) PCM Stream, in case you want to use an other DAC.
• Datasheet for the MSM6258 is available here (PDF)

Used in

Homecomputers

• Sharp X68000

Video Game Consoles

• NEC PC-FX (?)

Special Applications

• Sharp X68000 | Uses the MSM6258 together with an YM2151 (OPM)

Variants

• MSM6258 | Standalone version
• MSM6258V | CPU Interface version

Emulation

• Sharp X1 | Emulated in Hoot

Sound Creation

PCMCONV

• This is a DOS Application you can use to convert PCM Data to the X68000 4-bit ADPCM Data.
  Running it with the default settings should work fine already. If you want something else refer to the document thats included.

• usage: pcmconv input.wav output.wav
• download