Hey all, I'm making tons of progress on my APU. And I've got another question: is the Wiki diagram for the pulse channel correct?
It seems wrong to me because the Sweep unit modifies (in certain cases) the period fed to the timer. So really I think it should look more like the one in Blargg's apu_ref.txt:
The above is not exactly what Blargg's doc shows. I modified it a bit to follow the "look-and-feel" of the Wiki's other APU channel diagrams and removed the incorrect "/2" output of the Timer.
Code:
Timer ---> Sequencer Sweep Length Counter
| | |
| | |
v v v
Envelope -------> Gate-----> Gate -----> Gate ---> (to mixer)
| | |
| | |
v v v
Envelope -------> Gate-----> Gate -----> Gate ---> (to mixer)
It seems wrong to me because the Sweep unit modifies (in certain cases) the period fed to the timer. So really I think it should look more like the one in Blargg's apu_ref.txt:
Code:
Sweep ----> Timer
| |
| v
| Sequencer Length Counter
| | |
| | |
v v v
Envelope ------->Gate --------->Gate ---------->Gate ------>(to mixer)
| |
| v
| Sequencer Length Counter
| | |
| | |
v v v
Envelope ------->Gate --------->Gate ---------->Gate ------>(to mixer)
The above is not exactly what Blargg's doc shows. I modified it a bit to follow the "look-and-feel" of the Wiki's other APU channel diagrams and removed the incorrect "/2" output of the Timer.