First is a non-looped 17-byte sample, second is looped. First byte is a short "hill", the next bytes make larger "hills". All 17 bytes are looped. Recording and code:
Code:
lda #1 ; length = 17 bytes
sta $4013
; Play unlooped
lda #$0C
sta $4010
lda #$10
sta $4015
delay_msec 15
; Play looped
lda #$4C
sta $4010
lda #$10
sta $4015
delay_msec 30
sample:
.byte $0F
.byte $FF,$00,$FF,$00,$FF,$00,$FF,$00
.byte $FF,$00,$FF,$00,$FF,$00,$FF,$00