This doubt came into my min when I was programming the Arpeggio effect for DefleMask Tracker.
Thanks for all the information, after some thinking I have decided to make the speed of arpeggio selecteable, not like Renoise (speed-dependent), but not like FamiTracker and the others trackers that Shiru mentioned (constant).
I guess since that's how the NES does it, that's how jsr programmed it.
The hardware has no arpeggio feature, so there's no such thing as "how the NES does it".
Are..you sure? I'd really like to know your source of info since I'm very new to the inner workings of this genre and my only source is the Famitracker Wiki :\
Well if you know how the NES functions and how FT interacts with the NES's hardware, it's not difficult to wrap your head around how it handles arpeggios. Basically, when you use 0xy, the tracker tells the engine to rapidly shift between your base note, interval x and interval y once every time the audio engine is updated (that is, once every 60th/50th of a second for NTSC/PAL). The 2a03 doesn't have an "arp mode" per se, but it handles them that way.
I guess I don't know is what I'm saying. When I've heard hardware VGM it sounds like 60hz arps. So I just assume that it's a feature of the 2A03.
So does this mean that oldschool composers just wrote the arps into their instruments and that jsr wrote the 0xy effect for the ease of us users? Rather than implement an already existing feature of the 2A03?
...I suppose I should ask the same of the Axy effect. If this fade-in chart is from values defined on the chip or simply the doing of jsr.
There IS no "arp feature" built directly in the 2a03. Composers back in the day did use to write out their arps note by note. So yes, the 0xy effect is there for the sake of user-friendliness. Same goes for Axy, and most other effects of the sort (such as 3xx, which just "translates" the portamento between two notes into appropriate software pitch envelopes depending on the base and target notes and the speed defined).
There is no built-in 'arp feature' in any sound chip, actually, and very few chips has built-in pitch slide effects as well (2A03 has it for pulse channels, but it is rarely used). It is always done by the player in software.
Besides, I never ever use the arpeggio effect in the first place because I like having control over my arpeggios
Well, Famitracker was your first and unique tracker appears like, because Famitracker is the unique tracker with Macros commands (a MML feature), or do you use a very high BPM in order to make your own arpeggios?.
I use instruments for my arpeggios. And I've been using ModPlug Tracker for about a decade, though I'm not an expert at it, and I've never used its arpeggio feature...
Delek wrote:
I guess I don't know is what I'm saying. When I've heard hardware VGM it sounds like 60hz arps. So I just assume that it's a feature of the 2A03.
That's 'cause everything in 2A03 audio happens at 60 Hz. Hardware sweeps might happen at a finer granularity, I'm not sure and I never use them anyway, but everything else happens on 60 Hz boundaries. For example, if your song is 120 BPM, which doesn't divide neatly into 60 Hz frames, every note is quantized to the nearest 60 Hz boundary. (For this reason, some composers keep the tempo at 150 BPM and only alter the speed, because then they at least have control over this quantization if any is needed at all.)
This is why MML commands are divided into 'frames' -- they're tied to the system's frame rate. (It'd be nice if FamiTracker came up with some terminology so we can more easily distinguish 'frame' as in 60 Hz interval and 'frame' as in a section of the song, but eh.)
Weird terms from MML. 
