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Atari coding BBS
| Falcon registers question |
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Posted by: Sallafranque
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Feb,01.2011-23:01
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Hi,
I'm asking myself questions about some Falcon registers (for hatari emulator).
Maybe someone here could help me ?
$FFFF8006: Monitor Type BIT 7 6 (These 2 bits are duplicated in $FFFF82C0 (BIT 1 0))
00 - Monochrome (SM124)
01 - Color (SC1224)
10 - VGA Color
11 - Television
$FFFF8006: Memory configuration BIT 5 4
00 - 1Mb
01 - 4Mb
10 - 14Mb
11 - no boot !
Is this true ?
$FFFF8006 is read only, the 2 monitor bits seems to be copied into $ffff82c0.
But $ffff82c2 is read / write. So what happen to these 2 bits if I change their value while writing something to $FFFF82C2 ?
Do they are "sticked" to their "$FFFF8006" value ?
Do they are refreshed ? (when ?)
Do they keep the value I give to them in $FFFF82C2 ?
$FFFF8007 Falcon Bus Control
BIT 6 : F30 Start (0=Cold, 1=Warm)
BIT 5 : STe Bus Emulation (0=on)
BIT 3 : Blitter Flag (0=on, 1=off)
BIT 2 : Blitter (0=8mhz, 1=16mhz)
BIT 0 : 68030 (0=8mhz, 1=16mhz)
Is this correct ?
I've seen some hardware files when 0=on and some other where 0=off
$FFFF8201/03/0d : Video Base Hi/Mi/Lo
On Ste, when one writes to Hi or Mi register, low register is reset.
Is it still true for the Falcon ?
$FFFF8264.B|RW|VDL_HSH|H-Scroll Hi %____xxxx |F
$FFFF8265.B|RW|VDL_HSL|H-Scroll Lo - clears Line Wide %____xxxx |STE,F
Some docs indicates that $FFFF8264 exists for the Falcon.
Some other don't.
Where is the truth ?
For the sound now : $FFFF8920
I've read in a doc that STE values in the Falcon don't use the same frequencies as STE value in the STE ?
All docs say that Falcon STE sound is nute, 12517 Hz, 25033 Hz, 50066 Hz
But one doc says that Falcon STE sound is nute, 12292 Hz, 19668 Hz, 49170 Hz
Is this true ?
| | | Falcon:nute------STE: 6258 Hz--------------00 |F,STE
| | | Falcon:12292 Hz--STE:12517 Hz--------------01 |F,STE
| | | Falcon:19668 Hz--STE:25033 Hz--------------10 |F,STE
| | | Falcon:49170 Hz--STE:50066 Hz--------------11 |F,STE
$FFFF8802.B|rW|PSG_DAT|Write Data |
| | | PSG Register 14 - Port A %RICDPBAS |
| | | Reset IDE 0:no,1:reset (slow down)---+||||||| |F
| | | Internal Speaker 0:on,1:off-----------+|||||| |F
| | | Centronics Strobe----------------------+||||| |
| | | Reset DSP 0:no,1:reset------------------+|||| |F
| | | Printer Select In------------------------+||| |
| | | Drive B select 0:on,1:off-----------------+|| |
| | | Drive A select 0:on,1:off------------------+| |
| | | Side select 0:side1,1:side0-----------------+ |
| | | PSG Register 15 - Port B %xxxxxxxx |
| | | Centronics Data Port-----------------++++++++ |
What kind of DSP reset is done here ?
Is it a cold reset or a warm reset ?
Stop for now.
It makes enough questions.
Thanks in advance.
Regards
Laurent
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