NESdev Wiki, “APU Triangle”

Cite as: NESdev Wiki, “APU Triangle”
Original: https://www.nesdev.org/wiki/APU_Triangle
sha256: ebda85ee24d8c73ceb1a674e7b68cfb6ffce3c8ec89a6fe7b79b780c9c4d9b2f
Version: oldid 23816
Archived: https://web.archive.org/web/20260519162401/https://www.nesdev.org/wiki/APU_Triangle
Accessed: 2026-10-21
Licence: none stated on the page
Credit: NESdev Wiki editors (nesdev.org); see the page history.
Notes: Read from the Wayback capture of 2026-05-19 (revision 23816). Used for the 32-step sequence and the triangle frequency formula.

Cited on

The triangle channel steps a fixed 32-step sequence, 15 down to 0 and back up, at $f = f_{C P U} / (32 (t + 1))$ , so it has no duty or volume setting.	`leadleadlead`	Wiki
A note byte is an offset into `FreqRegLookupTbl`, a table of 51 two-byte timer periods that the driver writes to the channel's timer registers; a recreation turns period $t$ into $f_{C P U} / (16 (t + 1))$ Hz on a square channel and half that on the triangle.	`lead`	Code