Uploaded an archive with updated documentation.
While at it, given that I was asked for a source code example, I whipped up an AMOS Professional program that shows how to set up a PED81C screen and to perform some basic operations on it - hopefully, this will be easy to understand and also open the door to AMOS programmers. The program source is included in the archive.
'-----------------------------------------------------------------------------
'$VER: PED81C example 1.0 (c) 2023 RETREAM
'Legal terms: please refer to the accompanying documentation.
'www.retream.com/PED81C
'ped81c@retream.com
'-----------------------------------------------------------------------------
'-----------------------------------------------------------------------------
'DESCRIPTION
'This shows how to set up a PED81C screen and to perform some basic operations
'on it.
'Screen features:
' * equivalent to a 319x256 LORES screen
' * 160 dots wide raster
' * single buffer
' * blanked border
' * 64-bit bitplanes fetch mode
' * CMYW color model
'
'NOTES
'The code is written to be readable, not to be general-purpose/optimal.
'-----------------------------------------------------------------------------
'-----------------------------------------------------------------------------
'GLOBAL VARIABLES
Global RASTERADDRESS,RASTERWIDTH,RASTERHEIGHT,RASTERSIZE
RASTERWIDTH=160
RASTERHEIGHT=256
RASTERSIZE=RASTERWIDTH*RASTERHEIGHT
'-----------------------------------------------------------------------------
'MAIN
'Initialize everything.
_INITIALIZE_AMOS_ENVIRONMENT
_INITIALIZE_SCREEN
'If the initialization succeeded, load a picture into the raster and, in case
'of success, execute a simple effect on it.
If Param
_LOAD_PICTURE_INTO_RASTER["picture-160x256.raw"]
If Param
_TURN_DISPLAY_DMA_ON[0]
_RANDOMIZE_RASTER
_TURN_DISPLAY_DMA_OFF
End If
End If
'Deinitialize everything.
_DEINITIALIZE_SCREEN
_RESTORE_AMOS_ENVIRONMENT
'-----------------------------------------------------------------------------
'ROUTINES
Procedure _ALLOCATE_BITPLANE[BANKINDEX,SIZE]
'--------------------------------------------------------------------------
'DESCRIPTION
'Allocates a CHIP RAM buffer to be used as a bitplane.
'
'INPUT
'BANKINDEX = index of bank to use
'SIZE = size [bytes] of bitplane
'
'OUTPUT
'64-bit-aligned bitplane address (0 = error)
'
'WARNINGS
'The buffer must be freed with Erase BANKINDEX or Erase All.
'--------------------------------------------------------------------------
Trap Reserve As Chip Data BANKINDEX,SIZE+8
If Errtrap=0 Then A=(Start(BANKINDEX)+7) and $FFFFFFF8
End Proc[A]
Procedure _DEINITIALIZE_SCREEN
'--------------------------------------------------------------------------
'DESCRIPTION
'Deinitializes the screen.
'
'WARNINGS
'Can be called only if the display is off.
'--------------------------------------------------------------------------
Erase All
Doke $DFF1FC,0 : Rem FMODE
End Proc
Procedure _INITIALIZE_AMOS_ENVIRONMENT
'--------------------------------------------------------------------------
'DESCRIPTION
'Ensures the program cannot be interrupted or brought to back, and turns
'off the AMOS video system.
'--------------------------------------------------------------------------
Break Off
Amos Lock
Comp Test Off
Auto View Off
Update Off
Copper Off
_TURN_DISPLAY_DMA_OFF
End Proc
Procedure _INITIALIZE_SCREEN
'--------------------------------------------------------------------------
'DESCRIPTION
'Initializes the screen.
'
'OUTPUT
'-1/0 = OK/error
'
'WARNINGS
'_DEINITIALIZE_SCREEN[] must be called also in case of failure.
'
'NOTES
'Sets RASTERADDRESS.
'--------------------------------------------------------------------------
'Allocate the raster.
_ALLOCATE_BITPLANE[10,RASTERSIZE] : If Param=0 Then Pop Proc[0]
RASTERADDRESS=Param
'Allocate and fill the selector bitplanes.
_ALLOCATE_BITPLANE[11,RASTERSIZE] : If Param=0 Then Pop Proc[0]
B3A=Param
Fill B3A To B3A+RASTERSIZE,$55555555
_ALLOCATE_BITPLANE[12,RASTERSIZE] : If Param=0 Then Pop Proc[0]
B4A=Param
Fill B4A To B4A+RASTERSIZE,$33333333
'Set the chispet.
Doke $DFF100,$4241 : Rem BPLCON0
Doke $DFF102,$10 : Rem BPLCON1
Doke $DFF104,$224 : Rem BPLCON2
Doke $DFF106,$20 : Rem BPLCON3
Doke $DFF108,0 : Rem BPLMOD1
Doke $DFF10A,0 : Rem BPLMOD2
Doke $DFF092,$38 : Rem DDFSTRT
Doke $DFF094,$D0 : Rem DDFSTOP
Doke $DFF08E,$2C82 : Rem DIWSTRT
Doke $DFF090,$2CC1 : Rem DIWSTOP
Doke $DFF1E4,$A100 : Rem DIWHIGH
Doke $DFF1FC,$3 : Rem FMODE
'Set COLORxx.
Doke $DFF180,0
Doke $DFF182,$88
Doke $DFF184,$88
Doke $DFF186,$FF
Doke $DFF188,$0
Doke $DFF18A,$808
Doke $DFF18C,$808
Doke $DFF18E,$F0F
Doke $DFF190,$0
Doke $DFF192,$880
Doke $DFF194,$880
Doke $DFF196,$FF0
Doke $DFF198,$0
Doke $DFF19A,$888
Doke $DFF19C,$888
Doke $DFF19E,$FFF
'Build a Copperlist that sets the bitplanes pointers.
Cop Movel $E0,RASTERADDRESS
Cop Movel $E4,RASTERADDRESS
Cop Movel $E8,B3A
Cop Movel $EC,B4A
Cop Swap
End Proc[-1]
Procedure _LOAD_PICTURE_INTO_RASTER[FILEPATH$]
'--------------------------------------------------------------------------
'DESCRIPTION
'Loads a raw 8-bit chunky picture into the raster, ensuring that its size
'is correct.
'
'OUTPUT
'-1/0 = OK/error
'--------------------------------------------------------------------------
Trap Open In 1,FILEPATH$ : If Errtrap Then Pop Proc[0]
L=Lof(1)
Close(1)
If L<>RASTERSIZE Then Pop Proc[0]
Trap Bload FILEPATH$,RASTERADDRESS
End Proc[Errtrap=0]
Procedure _RANDOMIZE_RASTER
'--------------------------------------------------------------------------
'DESCRIPTION
'Randomizes the raster by swapping 16 dots per frame, until a mouse button
'is pressed.
'--------------------------------------------------------------------------
XM=RASTERWIDTH-1
YM=RASTERHEIGHT-1
Repeat
C=16
While C
X0=Rnd(XM)
Y0=Rnd(YM)
X1=Rnd(XM)
Y1=Rnd(YM)
A0=Y0*RASTERWIDTH+X0+RASTERADDRESS
A1=Y1*RASTERWIDTH+X1+RASTERADDRESS
C0=Peek(A0)
Poke A0,Peek(A1)
Poke A1,A0
Dec C
Wend
_WAIT_SCREEN_BOTTOM
Until Mouse Click
End Proc
Procedure _RESTORE_AMOS_ENVIRONMENT
'--------------------------------------------------------------------------
'DESCRIPTION
'Restores the AMOS environment.
'--------------------------------------------------------------------------
Copper On
Update On
Auto View On
Amos Unlock
Break On
_TURN_DISPLAY_DMA_ON[$20]
End Proc
Procedure _TURN_DISPLAY_DMA_OFF
'--------------------------------------------------------------------------
'DESCRIPTION
'Disables the bitplanes, Copper and sprites DMA.
'--------------------------------------------------------------------------
_WAIT_SCREEN_BOTTOM
Doke $DFF096,$3A0 : Rem DMACON
End Proc
Procedure _TURN_DISPLAY_DMA_ON[SSPRITESFLAG]
'--------------------------------------------------------------------------
'DESCRIPTION
'Enables the bitplanes and Copper DMA.
'
'INPUT
'SSPRITESFLAG = $20/0 = turn / do not turn sprites on
'
'WARNINGS
'The chipset must have been set up properly.
'--------------------------------------------------------------------------
_WAIT_SCREEN_BOTTOM
Doke $DFF096,$8380 or SSPRITESFLAG : Rem DMACON
End Proc
Procedure _WAIT_SCREEN_BOTTOM
'--------------------------------------------------------------------------
'DESCRIPTION
'Waits for the bottom of the screen.
'--------------------------------------------------------------------------
While Deek($DFF004) and $3 : Wend
Repeat : Until(Leek($DFF004) and $3FF00)>$12C00
End Proc
