Z89340 Datasheet, PDF (23/30 Pages) Zilog, Inc. – Digital Wavetable Engine

Z89340
Digital Wavetable Engine
Wave Endpoint Lo/
ROM2-ROM7
bits 2-7
AWS/Interleave Size
address 8
(Sample Loop Oscillator only)
ATFP Flags
bits 0 and 1
1 ^{For sample loop systems, Wave Endpoint is the last sam-}
ple in the sample sequence. When this last sample is
These bits are active for the selected envelope types in played, the Z89340 subtracts Wave Loop Length from the
Frequency Lo. The bits have a separate meaning for Wave Pointer. Note that since only six bits are available for
Tremolo from the other types.
Wave Endpoint Lo, the sample sequence can only end on
every fourth address. Wave Loop Length does not have
Amplitude/Filter/Pan envelope flag bits:
this restriction.
00-Off
01-Wait
10-In process
11-Done
Tremolo envelope flag bits:
bit 0-Enable
bit 1-Polarity
Interleave Size
bits 2-3
(Wavetable Mode Oscillator only)
With wavetable synthesis, one or more complete periods
of a waveform are stored in a wavetable. Interleave is the
distance between wavetables. Normally Interleave Size
will equal Table Size so that the wavetable will be contigu-
ous. For compatibility with existing sound libraries, other
interleaves are available.
00-64 Samples
01-128 Samples
10-256 Samples
11-512 Samples
AWS
bit 4
(Wavetable Mode Oscillator only)
With wavetable synthesis, one or more complete periods
of a waveform are stored in a wavetable. We Change the
Wave Endpoint when we want to move to the next wavet-
able. How the sound moves from the current wavetable to
the next is controlled by AWS (Automatic Wave Select).
When AWS is 0, the sound loops on the current wavetable
as long as Wave Endpoint equals Wave Pointer. When
Wave Endpoint is changed, the Z89340 jumps to the
wavetable pointed to by Wave Endpoint as soon as it plays
the last sample of the current wavetable pointed to by
Wave Pointer. Wave Pointer is then set equal to Wave
Endpoint. When AWS is 1, all samples in the wavetables
between Wave Pointer and Wave Endpoint are also
played. The Z89340 the loops on the wavetable pointed to
by Wave Endpoint.
Wave Endpoint Hi
address 9
ROM8-ROM15
(Refer to Wave Endpoint Lo.)
bits 0-7
Wave Loop Length Lo
address A
Table Size
bits 0 and 1
(Wavetable Mode Oscillator only)
With wavetable synthesis, one or more complete periods
of a waveform are stored in a wavetable. Table Size is the
size of the wavetable. Interleave is the distance between
wavetables. Normally Interleave Size will equal Table Size
so that the wavetable will be contiguous. For compatibility
with existing sound libraries, other interleaves are avail-
able.
00-64 Samples
01-128 Samples
10-256 Samples
11-512 Samples
ROM2-ROM7
bits 2-7
(Wavetable Mode Oscillator only)
For Wavetable Mode Oscillators, this should be 0.
ROM0-ROM7
bits 0-7
(Sample Loop Oscillator only)
A sample sequence is played by setting Wave Pointer to
the first sample in the sequence and Wave Endpoint to the
last sample in the sequence. For many sounds, we then
repeat or loop the last portion of the sequence. Wave Loop
Length is the length of the loop.
Wave Loop Length Hi
address B
ROM8-ROM15
bits 0-7
(Refer to Wave Loop Length Lo.)
For Wavetable Mode Oscillators, this should be 0.
ROM5-ROM7
bits 5-7
(Wavetable Mode Oscillator only)
With wavetable synthesis, one or more complete periods
of a waveform are stored in a wavetable. The wavetable
can be played at any desired frequency.
DS96DSP0201
PRELIMINARY
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