; The following was taken from Application Note AN3201-02
; Please refer to that document for more information
;
; File: AN3201-02U.asm
; Description: Example pitch up program
; Authors: Frank Thomson
; Copyright 2001 Alesis Semiconductor
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; 1 octave up
LFO0 SAW AMP=32767 FREQ=128 XFAD=1/16
;
;NOTE: Here we define the waveform:
; SIN, TRI (triangle), SAW (sawtooth for pitch shift)
;
;
MEM pitchmem 8200 ; Circular buffer memory
MEM temp 1 ; temp register
MEM temp2 1 ; temp register
;NOTE: memory locations are referenced by:
; name Start of memory block
; name' End of memory block
; name" Middle of memory block
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;
RZP ADCL K=.999 ;0 Read left channel into Accumulator
;
WZP pitchmem K=.999 ;1 Write to the start of the memoryblock
; Next read from the middle of the delay memory block using the chorus instruction
; to add the sawtooth waveform to the address.
; The sample returned is multiplied by the 1's comp of the
; coefficient from the chorus generator block. Use the SIN output for the first
; sawtooth. As this is a pitch up, 1's comp the address.
;
CHR0 RZP pitchmem" +SIN COMPA COMPK LATCH ;2
;
; Read the sample before the above one and multiply it by the coefficient.
;
CHR0 RAP pitchmem"+1 +SIN COMPA ;3 Read middle -1 from memory block
;
; Save the result to a temp register.
;
WAP temp K=0 ;4 Save result to temp location
;
; Now do it again using the COS output to get the other sawtooth
; Again inverting the address portion of the sawtooth
;
CHR0 RZP pitchmem" +COS COMPA COMPK LATCH ;5
CHR0 RAP pitchmem"+1 +COS COMPA ;6
;
; The result from the 2 instructions is in the accumulator, do a write to
; a temp location to bring it back through the multiplier and use the 1's comp of
; the cross fade coefficient to multiply it by.
;
CHR0 WZP temp2 +COS MASKA COMPK ;7
;
; Get the first result, multiply it by the cross fade coefficient and add it.
;
CHR0 RAP temp MASKA ;8
;
WAP OUTL K=0 ;9 Write it to the DAC
;
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;
RZP ADCL K=.999 ;10 Read left channel into Accumulator
WAP OUTR K=0 ;11 Write to right output
;
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;Add a bunch of reads for refresh
RZP 0x00 K=0
RZP 0x40 K=0
RZP 0x80 K=0
RZP 0xc0 K=0
RZP 0x100 K=0
RZP 0x140 K=0
RZP 0x180 K=0
RZP 0x1c0 K=0
RZP 0x200 K=0
RZP 0x240 K=0
RZP 0x280 K=0
RZP 0x2c0 K=0
RZP 0x300 K=0
RZP 0x340 K=0
RZP 0x380 K=0
RZP 0x3c0 K=0