furnace/doc/7-systems/msm6295.md

OKI MSM6295

this chip is an upgrade from the MSM6258 in that it provides 4 ADPCM channels at a fixed output rate up to 32 KHz depending on clock rate. between the late '80s and late '90s, it was one of the most common, if not the most common soundchip used in arcade machines: Capcom, Toaplan, Kaneko, Atari, Tecmo, the list can go on and on...

without bankswitching, the chip supports 256kB of sample RAM and can hold up to 127 samples at once.

effects

• 20xx: set chip output rate.
  • 0: /132
  • 1: /165

info

this chip uses the MSM6295 instrument editor.

when not bankswitched, maximum sample length is 522240 samples.

chip clock rates

like MSM6258, MSM6295 is an extremely basic ADPCM sound codec. it has no variable sample rate; it depends on clock rate of the chip itself. the clock can be divided by either 132 or by 165 to get the sample rates listed below:

clock rate	/132	/165
0.875 MHz	6629 Hz	5303 Hz
0.89 MHz	6742 Hz	5394 Hz
0.9375 MHz	7102 Hz	5682 Hz
1 MHz	7576 Hz	6061 Hz
1.02 MHz	7727 Hz	6182 Hz
1.056 MHz	8000 Hz	6400 Hz
1.193 MHz (Atari)	9038 Hz	7230 Hz
1.5 MHz	11364 Hz	9091 Hz
1.79 MHz	13561 Hz	10848 Hz
2 MHz	15152 Hz	12121 Hz
2.112 MHz	16000 Hz	12800 Hz
3 MHz	22728 Hz	18182 Hz
3.58 MHz	27122 Hz	21697 Hz
4 MHz	30304 Hz	24242 Hz
4.224 MHz	32000 Hz	25600 Hz

chip config

the following options are available in the Chip Manager window:

• Clock rate: sets the rate at which the chip will run.
• Output rate: sets the chip clock divider.
• Bankswitched: add an NMK112 chip to increase sample memory to 16MB and the maximum number of samples to 8192. each bank is up to 63KB with sample headers, and the maximum sample length is 129024 samples.