MOS8364 Paula

Do you know a source for a MOS8364 Paula datasheet ?

Not looking good: However: The MOS Technology 8364 Paula chip featured four independent 8-bit D/A converters. The Paula features four mono audio channels, or two combined stereo channels. Paula The Paula chip is mainly used to produce audio output. The chip has 4 DMA-driven 8-bit PCM sample sound channels. Two sound channels are mixed into the left audio output, and the other two are mixed into the right output, producing stereo audio output. The only supported hardware sample format is signed linear 8-bit two's complement. Each sound channel has an independent volume and frequency. Internally, the audio hardware is implemented by four state machines each having eight different states.

Additionally the hardware allows one channel in a channel pair to modulate the other channel's period or amplitude. It is rarely used on the Amiga due to both frequency and volume being controllable in better ways, but could be used to achieve different kinds of tremolo and vibrato, and even rudimentary FM synthesis effects.

With some special programming tricks it is possible to produce 14-bit audio by combining two channels set at different volumes, giving two 14-bit channels instead of four 8-bit channels. This is done by playing the high byte of a 16 bit sample at maximum volume, and the low byte at minimum volume.

On a regular NTSC or PAL screen display, audio playback, using DMA, is limited to a maximum sampling rate of 28867 Hz (PAL: 28837 Hz), due to the amount of data that can be fetched from memory in the time allocated to Paula. As explained in the discussion of Agnus, memory access is prioritized and only a few slots for memory access are available to Paula's sound channels. This limit can be overcome in the Enhanced Chip Set by using a higher frequency screen mode, or by using the CPU directly to drive audio output.

The Amiga contains an analog low-pass filter (reconstruction filter) which is external to Paula. The filter is a 12 dB/oct Butterworth low-pass filter at approximately 3.3 kHz. The filter can only be applied globally to all 4 channels. In models after the Amiga 1000, the brightness of the power LED is used to indicate the status of the filter. The filter is active when the LED is at normal brightness, and deactivated when dimmed (on early Amiga 500 models the LED went completely off). Models released before Amiga 1200 also have a static "tone knob" type low pass filter that is enabled regardless of the optional "LED filter". This filter is a 6 dB/oct low pass filter with cutoff frequency at 4.5 or 5 kHz.

Analog Devices is sending me some Octal 8-bit DACs:

So the functionality should be duplicatable ...