On Fri, 28 Oct 2016, Nicolas Pomarède wrote:
Apart from that, here're some things that could be measured on STE :
- set start=end, start dma sound with repeat off : does dma turns off
immediately or at the end of the next video line where FIFO would be
filled ?
Do we get the "end of frame" timer A interrupt in that case ?
I guess dma sound counter and bit 0 of ff8901 are updated at the end
of each line, when display enabled is set to off and shifter displays
border color.
Hello,
I tested this; set start and end the same, and start replay without
loop. I've also initialized Timer A in event mode to invert background
colour if it happens. I set event to 1 so it will interrupt after the
first loop.
Results:
- Hatari 2: noise played, no inverted background
- STe: silent, no inverted background
- if start=end and we start dma sound with repeat on, do we also get
an immediate end of frame timer A interrupt, just before dma address
goes beyond end address ? As the end condition seems to not be
correctly checked in that case, maybe the end of frame bit in the MFP
is not available either and we would not get an input on timer A in
event count mode ?
So the same program as above, but with loop.
- Hatari 2: noise played, no inverted background
- STe: a tiny click then silence, no inverted background
So it would seem with repeat the STe does play a little bit of data
before shutting off.
Maybe I did some mistake in the code, here it is for both tests:
http://ae.dhs.nu/tmp/hdma2.zip