ES1371 Datasheet, PDF (37/37 Pages) List of Unclassifed Manufacturers – ENSONIQ AudioPCI 97 digital controller

ENSONIQ Proprietary Information
15. APPENDIX
15.1. Bus Latency
Since each audio channel has a 64 byte buffer, the Latency requirement for the PCI bus can be
calculated as follows:
For 8 bit audio: 32 Samples (one half buffer) @ 44.1 kHz. = 725µsec.
For 16 bit audio: 16 Samples @ 44.1 kHz. = 363 µsec.
Therefore, once a Bus Request is made, AudioPCI 97 needs to have the PCI bus grant in 363 µsec. for 16
bit samples. In most game environments the sound effects are 8 bit and the high latency figure is
acceptable. If more than one channel needs servicing, this does not impact the latency calculation because
once the PCI Bus is granted it can be held until all channels are serviced. Since AudioPCI 97 uses 8 Long
Word burst transfers, each channel is filled with one burst transfer and AudioPCI 97 can service all three
with just 24 transfers.
15.2. Bus Bandwidth
The Bus bandwidth required by AudioPCI is very low. If all three channels are running at 44.1 kHz the
total bandwidth is:
44.1 kHz × 2 (stereo) × 3 (channels) × 2 (bytes) = 529 KBytes/sec.
This represents less than 0.5% of the available PCI Bus bandwidth.
ENSONIQ Proprietary Information
ENSONIQ AudioPCI 97 Specification Rev 1.1 Oct 1, 1997
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