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I tend to work on 4k files anyway (CHR and SPR separate), I just never realised that YYCHR creates an 8K file by default. :) I loaded up the CHR file for my latest project and messed around editing the nametable. I really like it, especially the inclusion of RLE. That's a really nice touch. Going to...

Cool! I'll be giving this a try. Couple of things immediately: + A really handy feature which I've never seen in one of these editors before is the ability to 'paint' attributes/palettes on the nametable. Really nice :D - I tried to load a .chr file that I'd made in YYCHR but your program wouldn't l...

Heh, typical.

I was actually writing $3F to $4011 and couldn't figure out why I still got the volume changing depending on whether I was using DCM or not.

At least I thought I did until I realised I put the $3F in the wrong place in my APU init table!

Thanks

What's the best way to constantly force the triangle and noise to output at the reduced level you get when using DCM?

I'm thinking it would be better for balancing channels if those two channels were always output as if you were playing DCM, even when you're not.

Seems like a good place and time to talk about my next project. I'm creating a drum (and bass-line) machine for the NES. + 6 virtual tracks, one drum sound assigned to each track + each drum sound can use all 5 or any combination of the NES's hardware voices + where two drum sounds require the same ...

I implemented a system similar to what I described. It's actually really good.

I'll try to distill the code down to something that I can post up here in case it's of any use to anyone else.

I'm sketching out high-level ideas for the screen writing code for my next project and have been trying to come up with a nice flexible and efficient DMA system. The general problems are; - there is too much information contained on the screen to write in one frame (as always) - there are several di...

That's very odd. I originally had the init routine from the wiki, verbatim, and I wasn't getting any noise output unless I wrote something to $400F at the time of writing the frequency register ($0E). So then I added the lines to write $00 to $4015 before the loop and $0F after the loop, just clutch...

Just stripped it all down to this; reset: sei ldx #$FF txs lda #$00 sta PPU0 sta PPU1 jsr init_APU mainLoop: jmp mainLoop nmi: rti irq: rti init_APU: lda #$00 sta $4015 ldx #$00 @a: lda @apu_regs,x sta $4000,x inx cpx #$18 bne @a lda #$0F sta $4015 lda #%00111111 sta $400c lda #$01 sta $400e ;sta $4...

blargg wrote:The code from the Wiki works fine for me (testing on a PAL NES at the moment). I do notice that your code plays a very quiet noise either way, maybe that's the problem.

Odd. It plays full volume here. Definitely not a volume issue.

*shrugs* I'm baffled.

Here's a big APU gotcha: Even if you're not using the sweep unit, you must still write 0x08 to the sweep register, otherwise it won't play the lowest notes. Yep, nasty one for the beginner that. Re. the noise thing. I need to do another test (just about to run out the door) but if you copy the apu ...

I think I'm going a bit mental. It's not like I haven't programmed NES audio before but if I do this; lda #$0F sta $4015 lda #%00111111 sta $400c lda #$00 sta $400e I get nothing. But if I do; lda #$0F sta $4015 lda #%00111111 sta $400c lda #$00 sta $400e sta $400f I get noise, as expected. I'm pret...

One odd thing about the linked page is that he looks at the fade waveforms in the linear space, even though we perceive it in an exponential space. In other words, his exponential fade is really linear, getting louder uniformly, while his linear fade is really exponential, getting loud quickly, the...

I see; I figured you might just initialize lfoCounter to lfoSpeed/2 when starting the LFO. That's quite a nice idea actually. It only falls down if the speed is an odd number as you'll end up with the median pitch moving away from the original slightly. I guess you could look at it the other way an...

Well, that costs you quite a few cycles. I was also wondering why you used bit 1 of lfoPhase rather than bit 0. It seems that this merely halves the speed. Because the phase has four states: %00 = up, %11 = down, %10 = down, %01 = up to give you the necessary cycle shape: /\ ----------- center freq...