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200Hz SNDH-replay using TimerC
Posted by: Sdw May,21.2015-15:31 

Hi!

I've gotten a tune from a musician that seems to want to be replayed at 200Hz. So far I've only used 50Hz tunes that I call in the VBL.

Looking at the SNDH I can see that it has a TC200 in the header where the old tunes have TC50, so it definitely wants to be replayed at 200Hz.

I've been trying to set up TIMER C to do this, and I think I have it working.

Here's some snippets from my init-code:

[code]
move.l $70.w,save_vbl ;Save old VBL
move.l $68.w,save_hbl ;Save old HBL
move.l $134.w,save_ta ;Save old Timer A
move.l $120.w,save_tb ;Save old Timer B
move.l $114.w,save_tc ;Save old Timer C
move.l $110.w,save_td ;Save old Timer D
move.l $118.w,save_acia ;Save old ACIA
move.l #vbl,$70.w ;Install our own VBL
move.l #dummy,$68.w ;Install our own HBL (dummy)
move.l #dummy,$134.w ;Install our own Timer A (dummy)
move.l #dummy,$120.w ;Install our own Timer B (dummy)
move.l #timer_c,$114.w ;Install our own Timer C
move.l #dummy,$110.w ;Install our own Timer D (dummy)
move.l #dummy,$118.w ;Install our own ACIA (dummy)
move.b $fffffa09.w,save_intb ;Save MFP state for interrupt enable B
move.b $fffffa15.w,save_intb_mask ;Save MFP state for interrupt mask B
clr.b $fffffa07.w ; Interrupt enable A (Timer-A & B)
clr.b $fffffa13.w ;Interrupt mask A (Timer-A & B)
move.b #%00100000,$fffffa09.w ;Interrupt enable B (Timer-C & D)
move.b #%00100000,$fffffa15.w ;Interrupt mask B (Timer-C & D)
[/code]

And here's my timer_c code:
[code]
timer_c:
movem.l a0-a6/d0-d7,-(sp)
jsr sndh+8
movem.l (sp)+,a0-a6/d0-d7
rte
[/code]

Now, I know that I haven't set up all the timer C stuff, the only thing I have done is enable it using $fffffa09 and $fffffa15, but looking at the documentation there is a lot of other stuff with dividers and "timer C data" (?).
Do I need to set up that as well, or will the code I have work on all systems - ie. I can expect it to be a nice 200Hz timer with the default settings?




[All messages in this thread]

Topic Posted by  Date 
200Hz SNDH-replay using TimerC Sdw May,21.2015-15:31
  Re: 200Hz SNDH-replay using TimerC gwEm/PHF May,21.2015-16:00
    Re: 200Hz SNDH-replay using TimerC Sdw May,21.2015-16:16
      Re: 200Hz SNDH-replay using TimerC evil May,21.2015-18:40
        Re: 200Hz SNDH-replay using TimerC Sdw May,27.2015-16:39
          Re: 200Hz SNDH-replay using TimerC evil May,27.2015-17:52
            Re: 200Hz SNDH-replay using TimerC Sdw May,27.2015-23:58
              Re: 200Hz SNDH-replay using TimerC gwEm/PHF May,28.2015-16:42
                Re: 200Hz SNDH-replay using TimerC evil May,28.2015-17:16
                  Re: 200Hz SNDH-replay using TimerC Splash/S1 May,29.2015-00:58
                    Re: 200Hz SNDH-replay using TimerC evil May,29.2015-11:56
                      Re: 200Hz SNDH-replay using TimerC gwEm/PHF May,29.2015-15:13
                        Re: 200Hz SNDH-replay using TimerC Splash/S1 May,31.2015-19:21
                  Re: 200Hz SNDH-replay using TimerC Sdw May,31.2015-21:49
                    Re: 200Hz SNDH-replay using TimerC insane Jun,07.2016-10:08
                      Re: 200Hz SNDH-replay using TimerC insane Jun,07.2016-10:29
                      Re: 200Hz SNDH-replay using TimerC Splash/Sector One Jun,30.2016-18:30


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