IO Pages: Difference between revisions

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Line 22: Line 22:
|$C000 - $C0FF
|$C000 - $C0FF
|$F0:0000 - $F0:00FF
|$F0:0000 - $F0:00FF
|
|RW
|
|
|Blue gamma conversion table
|Blue gamma conversion table
Line 28: Line 28:
|$C400 - $C4FF
|$C400 - $C4FF
|$F0:0400 - $F0:04FF
|$F0:0400 - $F0:04FF
|
|RW
|
|
|Green gamma conversion table
|Green gamma conversion table
Line 34: Line 34:
|$C800 - $C8FF
|$C800 - $C8FF
|$F0:0800 - $F0:08FF
|$F0:0800 - $F0:08FF
|
|RW
|
|
|Red gamma conversion table
|Red gamma conversion table
|}
|}
Each area is 256 bytes, mapping an 8-bit value (offset) to an 8-bit value (memory value), mirrored 4 times currently to fill each 1kB address space.


====== $CC00: Mouse Pointer Bitmap ======
====== $CC00: Mouse Pointer Bitmap ======
Line 50: Line 51:
|$CC00 - $CCFF
|$CC00 - $CCFF
|$F0:0C00 - $F0:0CFF
|$F0:0C00 - $F0:0CFF
|
|RW
|
|
|Mouse pointer bitmap (16×16 greyscale bytes)
|Mouse pointer bitmap (16×16 greyscale bytes)
|}
|}
This is currently mirrored 4 times in $CC00 - $CFFF.


===== $D000: Master Control Registers =====
===== $D000: VICKY Config =====
 
====== $D000: Master Control Registers ======
{| class="wikitable"
{| class="wikitable"
!MMU
!MMU
Line 847: Line 851:
| colspan="8" |PSG Right
| colspan="8" |PSG Right
|}
|}
Note the stereo separation is controlled with the '''PSG_ST''' flag.
Stereo separation is enabled with the '''[[IO Pages#$D6A0: System Control Registers|PSG_ST]]''' flag. By default, both PSGs go to both speakers.


====== $D620: CODEC ======
====== $D620: CODEC ======
Line 2,051: Line 2,055:
| colspan="8" |0: 32×32
| colspan="8" |0: 32×32
1: 24×24
1: 24×24
2: 16×16
2: 16×16
3: 8×8
3: 8×8
|-
|-
Line 2,077: Line 2,083:
====== $DB00: VIAs ======
====== $DB00: VIAs ======
See: [[Keyboard raw codes]]
See: [[Keyboard raw codes]]
<nowiki>*</nowiki> = F256k series only
{| class="wikitable"
{| class="wikitable"
!MMU
!MMU
Line 2,091: Line 2,099:
!0
!0
|-
|-
|$DB00
|$DB00*
|$F0:1B00
|$F0:1B00*
|
|
|VIA1
|VIA1
| colspan="8" |Internal Keyboard VIA (F256k series only!)
| colspan="8" |Internal Keyboard VIA*
|-
|-
|$DC00
|$DC00
Line 2,108: Line 2,116:
|IORB
|IORB
| colspan="8" |Port B Data
| colspan="8" |Port B Data
|-
|
|
|
|
| colspan="8" |VIA0: Joystick 0, keyboard column 8*
VIA1: Keyboard columns 0-7*
|-
|-
|
|
Line 2,114: Line 2,129:
|IORA
|IORA
| colspan="8" |Port A Data
| colspan="8" |Port A Data
|-
|
|
|
|
| colspan="8" |VIA0: Joystick 1
VIA1: Keyboard row*
|-
|-
|
|
Line 2,202: Line 2,224:
| colspan="8" |Port A Data (no handshake)
| colspan="8" |Port A Data (no handshake)
|}
|}
====== $DD00: SD Card Controller ======
{| class="wikitable"
{| class="wikitable"
!MMU
|+VIA0 Joystick Bits
!Flat
!R/W
!Name
!7
!7
!6
!6
Line 2,218: Line 2,235:
!0
!0
|-
|-
|$DD00
|Keyboard column 8*
|$F0:1D00
|Button 2
|RW
|Button 1
|Button 0
|Right
|Left
|Down
|Up
|}
{| class="wikitable"
|+VIA1 Internal Keyboard Matrix*
!
!PB0
!PB1
!PB2
!PB3
!PB4
!PB5
!PB6
!PB7
!VIA0 PB7
|-
|'''PA0'''
|Del
|Return
|Left
|F7
|F1
|F3
|F5
|Up
|Down
|-
|'''PA1'''
|3
|W
|A
|4
|Z
|S
|E
|LShift
|
|
|SPI_BUSY
|—
|—
|—
|—
|—
|SPI_CLK
|CS_EN
|-
|-
|$DD01
|'''PA2'''
|$F0:1D01
|5
|RW
|R
|D
|6
|C
|F
|T
|X
|
|-
|'''PA3'''
|7
|Y
|G
|8
|B
|H
|U
|V
|
|-
|'''PA4'''
|9
|I
|J
|0
|M
|K
|O
|N
|
|-
|'''PA5'''
| -
|P
|L
|Caps
|.
|;
|[
|,
|
|-
|'''PA6'''
|=
|]
|'
|Home
|RShift
|Alt
|Tab
|/
|Right
|-
|'''PA7'''
|1
|BS
|Ctrl
|2
|Space
|Foenix
|Q
|Run/Stop
|
|
| colspan="8" |SPI_DATA
|}
|}
'''SPI_CLK''': 400MHz init clock when set, 12.5MHz standard clock when clear.


====== $DD40: F256K2 Case LCD Screen ======
====== $DD00: SD Card Controllers ======
Main page: [[Use the K2 LCD]]
{| class="wikitable"
{| class="wikitable"
!MMU
!MMU
Line 2,255: Line 2,361:
!0
!0
|-
|-
|$DD40
|$DD00
|$F0:1D40
|$F0:1D00
|
|
|LCD_CMD_CMD
|
| colspan="8" |Command
| colspan="8" |SD Card 0 (external)
|-
|-
|$DD41
|$DD20
|$F0:1D41
|$F0:1D20
|
|
|
|LCD_CMD_DTA
| colspan="8" |SD Card 1 (internal)
| colspan="8" |Data
|-
|-
|$DD42
|$F0:1D42
|
|
|LCD_PIX_LO
| +0
| colspan="3" |Green[2:0]
|RW
| colspan="5" |Blue
|
|SPI_BUSY
|—
|—
|—
|
|
|SPI_CLK
|CS_EN
|-
|-
|$DD43
|$F0:1D43
|
|
|LCD_PIX_HI
| +1
| colspan="5" |Red
|RW
| colspan="3" |Green[5:3]
|
| colspan="8" |SPI_DATA
|}
|}
'''SPI_CLK''': 400MHz init clock when set, 12.5MHz standard clock when clear.


===== $DDA0: SAM2695 MIDI (F256K series only) =====
====== $DD40: F256K2 Case LCD Screen ======
Main page: [[Use the Sam2695 Dream MIDI chip]]
Main page: [[Use the K2 LCD]]
{| class="wikitable"
{| class="wikitable"
!MMU
!MMU
Line 2,298: Line 2,410:
!0
!0
|-
|-
|$DDA0
|$DD40
|$F0:1DA0
|$F0:1D40
|R
|
|MIDI_STATUS
|LCD_CMD_CMD
|TX_EMPTY
| colspan="8" |Command
|RX_FULL
|—
|—
|—
|—
|—
|
|-
|-
|$DDA1
|$DD41
|$F0:1DA1
|$F0:1D41
|RW
|
|MIDI_FIFO_DATA_PORT
|LCD_CMD_DTA
| colspan="8" |Data
| colspan="8" |Data
|-
|-
|$DDA2
|$DD42
|$F0:1DA2
|$F0:1D42
|
|
|MIDI_RXD_COUNT
|LCD_PIX_LO
| colspan="8" |Rx FIFO Data count (12-bit)
| colspan="3" |Green[2:0]
|-
| colspan="5" |Blue
|$DDA4
|-
|$F0:1DA4
|$DD43
|
|$F0:1D43
|MIDI_TXD_COUNT
|
| colspan="8" |Tx FIFO Data Count (12-bit)
|LCD_PIX_HI
|}
| colspan="5" |Red
 
| colspan="3" |Green[5:3]
===== $DE00: Integer Math Coprocessor =====
|}
{| class="wikitable"
 
!MMU
===== $DDA0: SAM2695 MIDI (F256 Gen 2 only) =====
!Flat
Main page: [[Use the Sam2695 Dream MIDI chip]]
!R/W
{| class="wikitable"
!Name
!MMU
!7
!Flat
!6
!R/W
!5
!Name
!4
!7
!3
!6
!2
!5
!1
!4
!0
!3
|-
!2
|$DE00
!1
|$F0:1E00
!0
|RW
|-
|MULU_A
|$DDA0
| colspan="8" |Multiplication A (Unsigned 16-bit)
|$F0:1DA0
|-
|R
|$DE02
|MIDI_STATUS
|$F0:1E02
|TX_EMPTY
|RW
|RX_FULL
|MULU_B
|—
|—
|—
|—
|—
|—
|-
|$DDA1
|$F0:1DA1
|RW
|MIDI_FIFO_DATA_PORT
| colspan="8" |Data
|-
|$DDA2
|$F0:1DA2
|
|MIDI_RXD_COUNT
| colspan="8" |Rx FIFO Data count (12-bit)
|-
|$DDA4
|$F0:1DA4
|
|MIDI_TXD_COUNT
| colspan="8" |Tx FIFO Data Count (12-bit)
|}
 
===== $DDC0: Optical Keyboard Controller (F256K2 Only) =====
{| class="wikitable"
!MMU
!Flat
!R/W
!Name
!7
!6
!5
!4
!3
!2
!1
!0
|-
|$DDC0
|$F0:1DC0
|
|OPT_KBD_DATA
| colspan="8" |FIFO queue. Each event is two 8-bit reads from here
|-
|$DDC1
|$F0:1DC1
|R
|OPT_KBD_STATUS
|MECH
|—
|—
|—
|—
|—
|—
|FIFO_EMPTY
|-
|
|
|
|
| colspan="8" |MECH = No optical keyboard if set
|-
|$DDC2
|$F0:1DC2
|
|OPT_KB_COUNT
| colspan="8" |Number of events in optical keyboard queue (12-bit)
|}
 
===== $DE00: Integer Math Coprocessor =====
{| class="wikitable"
!MMU
!Flat
!R/W
!Name
!7
!6
!5
!4
!3
!2
!1
!0
|-
|$DE00
|$F0:1E00
|RW
|MULU_A
| colspan="8" |Multiplication A (Unsigned 16-bit)
|-
|$DE02
|$F0:1E02
|RW
|MULU_B
| colspan="8" |Multiplication B (Unsigned 16-bit)
| colspan="8" |Multiplication B (Unsigned 16-bit)
|-
|-
Line 2,489: Line 2,691:
| colspan="8" |Destination stride (16-bit, 2D mode)
| colspan="8" |Destination stride (16-bit, 2D mode)
|}
|}
DMA only runs during VBlank, and halts the CPU to take over the entire bus. This runs at 100MHz, at 8 bits (gen 1) or 16 bits (gen 2) wide.


== IO Page 1 ==
== IO Page 1 ==
Line 2,502: Line 2,705:
|$C000 - $C7FF
|$C000 - $C7FF
|$F0:2000 - $F0:27FF
|$F0:2000 - $F0:27FF
|
|RW
|
|
|Font set 0 (256 × 8-byte chars)
|Font set 0 (256 × 8-byte chars)
Line 2,508: Line 2,711:
|$C800 - $CFFF
|$C800 - $CFFF
|$F0:2800 - $F0:2FFF
|$F0:2800 - $F0:2FFF
|
|RW
|
|
|Font set 1 (256 × 8-byte chars)
|Font set 1 (256 × 8-byte chars)
Line 2,524: Line 2,727:
|$D000 - $D3FF
|$D000 - $D3FF
|$F0:3000 - $F0:33FF
|$F0:3000 - $F0:33FF
|
|RW
|
|
|Graphics CLUT 0 (256 × [[IO Pages#BGRx|BGRx]])
|Graphics CLUT 0 (256 × [[IO Pages#BGRx|BGRx]])
Line 2,530: Line 2,733:
|$D400 - $D7FF
|$D400 - $D7FF
|$F0:3400 - $F0:37FF
|$F0:3400 - $F0:37FF
|
|RW
|
|
|Graphics CLUT 1 (256 × [[IO Pages#BGRx|BGRx]])
|Graphics CLUT 1 (256 × [[IO Pages#BGRx|BGRx]])
Line 2,536: Line 2,739:
|$D800 - $DBFF
|$D800 - $DBFF
|$F0:3800 - $F0:3BFF
|$F0:3800 - $F0:3BFF
|
|RW
|
|
|Graphics CLUT 2 (256 × [[IO Pages#BGRx|BGRx]])
|Graphics CLUT 2 (256 × [[IO Pages#BGRx|BGRx]])
Line 2,542: Line 2,745:
|$DC00 - $DFFF
|$DC00 - $DFFF
|$F0:3C00 - $F0:3FFF
|$F0:3C00 - $F0:3FFF
|
|RW
|
|
|Graphics CLUT 3 (256 × [[IO Pages#BGRx|BGRx]])
|Graphics CLUT 3 (256 × [[IO Pages#BGRx|BGRx]])

Latest revision as of 18:10, 26 October 2025

More detailed information is found in the Manuals.

Notes

SRAM Address: Raw addresses for the system SRAM chip. The VICKY can only address the system SRAM (for now, DDR3 support coming). The 1st gen hardware has 512kB (19-bit space), while the 2nd gen has 2MB (21-bit space). The 24-bit pointers used are direct addresses into the SRAM chip, regardless of how the 2MB is mapped to the CPU's/MMU's address space. For instance, Core2x has 4 separate 512kB banks at non-consecutive addresses; these 4 banks are all linear+consecutive in the SRAM, and that view must be addressed here instead of its 24-bit CPU-visible addresses.

Model names: Certain features are only available on certain models, and these terms are used exactly. For instance, "F256Jr" means exactly the 1st gen Jr, not the entire Jr line.

BGR: A 3-byte color entry in Blue, Green, Red order.

BGRx: A 4-byte aligned color entry in Blue, Green, Red order, with the 4th byte unused.

IO Page 0

$C000 Gamma Lookup
MMU Flat R/W Name Description
$C000 - $C0FF $F0:0000 - $F0:00FF RW Blue gamma conversion table
$C400 - $C4FF $F0:0400 - $F0:04FF RW Green gamma conversion table
$C800 - $C8FF $F0:0800 - $F0:08FF RW Red gamma conversion table

Each area is 256 bytes, mapping an 8-bit value (offset) to an 8-bit value (memory value), mirrored 4 times currently to fill each 1kB address space.

$CC00: Mouse Pointer Bitmap

See: Use the PS/2 Mouse

MMU Flat R/W Name Description
$CC00 - $CCFF $F0:0C00 - $F0:0CFF RW Mouse pointer bitmap (16×16 greyscale bytes)

This is currently mirrored 4 times in $CC00 - $CFFF.

$D000: VICKY Config
$D000: Master Control Registers
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D000 $F0:1000 RW MSTR_CTRL_0 GAMMA SPRITE TILE BITMAP GRAPH OVRLY TEXT
$D001 $F0:1001 RW MSTR_CTRL_1 FON_SET FON_OVLY MON_SLP DBL_Y DBL_X CLK_70

TEXT: Enable text layer

OVRLY: Overlay text on graphics, by making text background transparent. See FON_OVLY

GRAPH: Enable graphics layers (tile, sprites, bitmaps)

BITMAP: Enable bitmap layers (if GRAPH is also set)

TILE: Enable tile layers (if GRAPH is also set)

SPRITE: Enable sprite layers (if GRAPH is also set)

GAMMA: Enable gamma correction

CLK_70: Enable 400p70, else 480p60

DBL_X, DBL_Y: Double text mode character width & height

MON_SLP: Turn off monitor SYNC, putting it into sleep mode

FON_OVLY: Only BG color 0 is transparent in OVRLY mode. Else, all BG colors are transparent.

FON_SET: Chooses font set 0 or 1

$D002: Layers
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D002 $F0:1002 RW Layer 1 Layer 0
$D003 $F0:1003 RW Layer 2
Values 0-2: Bitmap 0-2

4-6: Tilemap 0-2

$D004: Border
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D004 $F0:1004 RW BRDR_CTRL SCROLL_X ENABLE
$D005 $F0:1005 RW BRDR_BLUE Border color Blue component
$D006 $F0:1006 RW BRDR_GREEN Border color Green component
$D007 $F0:1007 RW BRDR_RED Border color Red component
$D008 $F0:1008 RW BRDR_WIDTH SIZE_X
$D009 $F0:1009 RW BRDR_HEIGHT SIZE_Y
$D00D: Background
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D00D $F0:100D RW BGND_BLUE Background color Blue component
$D00E $F0:100E RW BGND_GREEN Background color Green component
$D00F $F0:100F RW BGND_RED Background color Red component
$D010: Text Cursor
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D010 $F0:1010 RW CCR FLASH_DIS RATE ENABLE
RATE 0: 1 second

1: 1/2 second 2: 1/4 second 3: 1/8 second

$D012 $F0:1012 RW CCH Cursor character code
$D014 $F0:1014 RW CURX Cursor X position (16-bit)
$D016 $F0:1016 RW CURY Cursor Y position (16-bit)
$D018: Raster
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D018 $F0:1018 R RAST_COL Raster current column (12-bit)
$D01A $F0:101A R RAST_ROW Raster current row (12-bit)
$D018 $F0:1018 W LINT_CTRL ENABLE
$D019 $F0:1019 W LINT_L Line interrupt line (12-bit)
$D100: Bitmaps
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D100 $F0:1100 Bitmap 0
$D108 $F0:1108 Bitmap 1
$D110 $F0:1110 Bitmap 2
+0 RW CLUT ENABLE
+1 RW SRAM Address of pixels (24-bit)
$D200: Tilemaps
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D200 $F0:1200 Tilemap 0
$D20C $F0:120C Tilemap 1
$D218 $F0:1218 Tilemap 2
+$00 W TILE_SIZE_8 ENABLE
+$01 W SRAM Address of tile map entries (24-bit)
+$04 W MAP_SIZE_X (8-bit)
+$06 W MAP_SIZE_Y (8-bit)
+$08 W X[3:0] SSX
+$09 W X[9:4]
+$0A W Y[3:0] SSY
+$0B W Y[7:4]
$D280: Tilesets
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D280 $F0:1280 Tileset 0
$D284 $F0:1284 Tileset 1
$D288 $F0:1288 Tileset 2
$D28C $F0:128C Tileset 3
$D290 $F0:1290 Tileset 4
$D294 $F0:1294 Tileset 5
$D298 $F0:1298 Tileset 6
$D29C $F0:129C Tileset 7
+0 W SRAM Address of tile pixels (24-bit)
+3 W SQUARE
$D400: Sound
$D400: SID chips
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D400 $F0:1400 Left SID
$D500 $F0:1500 Right SID
+$00 W Voice 1 Frequency (16-bit)
+$02 W Pulse width (12-bit)
+$04 W NOISE PULSE SAW TRI TEST RING SYNC GATE
+$05 W ATTACK DELAY
+$06 W SUSTAIN RELEASE
+$07 W Voice 2 Frequency (16-bit)
+$09 W Pulse width (12-bit)
+$0B W NOISE PULSE SAW TRI TEST RING SYNC GATE
+$0C W ATTACK DELAY
+$0D W SUSTAIN RELEASE
+$0E W Voice 3 Frequency (16-bit)
+$10 W Pulse width (12-bit)
+$12 W NOISE PULSE SAW TRI TEST RING SYNC GATE
+$13 W ATTACK DELAY
+$14 W SUSTAIN RELEASE
+$15 W Misc FC[2:0]
+$16 W FC[10:3]
+$17 W RESONANCE EXT FILTV3 FILTV2 FILTV1
+$18 W MUTEV3 HIGH BAND LOW VOLUME
$D580: OPL3 (NOT on F256Jr!)

Main page: Use the OPL3 YMF262

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D580 $F0:1580 W Address registers for ports $000 - $0FF
$D581 $F0:1581 W Data registers for all ports
$D582 $F0:1582 W Address register for ports $100 - $1FF
$D600: PSGs

Main page: Use the PSG

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D600 $F0:1600 PSG Left
$D608 $F0:1608 PSG Left + Right
$D610 $F0:1610 PSG Right

Stereo separation is enabled with the PSG_ST flag. By default, both PSGs go to both speakers.

$D620: CODEC

Main page: Use the CODEC

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D620 $F0:1620 W DATA[7:0]
$D621 $F0:1621 W REGISTER DATA[8]
$D622 $F0:1622 R BUSY
W START
$D630: System
$D630: UART
MMU Flat R/W Name 7 6 5 4 3 2 1 0
DLAB = 0
$D630 $F0:1630 R RXD RX_DATA
W TXR TX_DATA
$D631 $F0:1631 RW IER STAT ERR TXE RXA
DLAB = 1
$D630 $F0:1630 RW DL DIV (16-bit)
$D632 $F0:1632 R IIR FIFO FIFO64 STATE /PENDING
W FCR RXT FIFO64 DMA TXR RXR FIFOE
$D633 $F0:1633 RW LCR DLAB PARITY STOP DATA
$D640: PS/2

See: Use the PS/2 Mouse

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D640 $F0:1640 RW PS2_CTRL MCLR KCLR M_WR K_WR
$D641 $F0:1641 RW PS2_OUT Data to keyboard
$D642 $F0:1642 R KBD_IN Data in from keyboard FIFO
$D643 $F0:1643 R MS_IN Data in from mouse FIFO
$D644 $F0:1644 R PS2_STAT K_AK K_NK M_AK M_NK MEMP KEMP
$D650: Timers
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D650 $F0:1650 W T0_CTR UP LD CLR EN
R T0_STAT EQ
$D651 $F0:1651 RW T0_VAL VAL (24-bit)
$D654 $F0:1654 RW T0_CMP_CTR RELD RECLR
$D655 $F0:1655 RW T0_CMP CMP (24-bit)
$D658 $F0:1658 W T1_CTR UP LD CLR EN
R T1_STAT EQ
$D659 $F0:1659 RW T1_VAL VAL (24-bit)
$D65C $F0:165C RW T1_CMP_CTR RELD RECLR
$D65D $F0:165D RW T1_CMP CMP (24-bit)
$D660: Interrupts

Main page: IRQ, IRQ Programming

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D660 $F0:1660 INT_PENDING Per-interrupt flags (24-bit)
$D664 $F0:1664 INT_POLARITY Per-interrupt flags (24-bit)
$D668 $F0:1668 INT_EDGE Per-interrupt flags (24-bit)
$D66C $F0:166C INT_MASK Per-interrupt flags (24-bit)
+0 & $01 INT_VKY_SOF Start of Frame interrupt (beginning of VSYNC)
+0 & $02 INT_VKY_SOL Start of Line interrupt
+0 & $04 INT_PS2_KBD PS/2 keyboard event
+0 & $08 INT_PS2_MOUSE PS/2 mouse event
+0 & $10 INT_TIMER_0 TIMER0 has reached its target value
+0 & $20 INT_TIMER_1 TIMER1 has reached its target value
+0 & $80 INT_CARTRIDGE Interrupt asserted from cartridge port
+1 & $01 INT_UART The UART is ready to receive or send data
+1 & $10 INT_RTC Interrupt from real time clock chip
+1 & $20 INT_VIA0 Event from the joystick VIA chip
+1 & $40 INT_VIA1 Event from the keyboard VIA chip (F256k Series Only!)
+1 & $80 INT_SDC_INS SD Card has been inserted
+2 & $01 IEC_DATA_i IEC data in
+2 & $02 IEC_CLK_i IEC clock in
+2 & $04 IEC_ATN_i IEC attention in
+2 & $08 IEC_SREQ_i IEC service request in
$D670: DIP Switches

Main page: DIP switches

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D670 $F0:1670 R GAMMA USER2 USER1 USER0 BOOT
$D680: IEC
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D680 $F0:1680 R IEC_I SRQ_i ATN_i CLK_i DAT_i
$D681 $F0:1681 RW IEC_O SRQ_o RST_o NMI_EN ATN_o CLK_o DAT_o
$D690: RTC
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D690 $F0:1690 RW Seconds 0 10s digit 1s digit
$D691 $F0:1691 RW Seconds Alarm 0 10s digit 1s digit
$D692 $F0:1692 RW Minutes 0 10s digit 1s digit
$D693 $F0:1693 RW Minutes Alarm 0 10s digit 1s digit
$D694 $F0:1694 RW Hours AM/PM 0 10s digit 1s digit
$D695 $F0:1695 RW Hours Alarm AM/PM 0 10s digit 1s digit
$D696 $F0:1696 RW Days 0 0 10s digit 1s digit
$D697 $F0:1697 RW Days Alarm 0 0 10s digit 1s digit
$D698 $F0:1698 RW Day of Week 0 0 0 0 0 1s digit
$D699 $F0:1699 RW Month 0 0 0 10s digit 1s digit
$D69A $F0:169A RW Year 10s digit 1s digit
$D69B $F0:169B RW Rates 0 WD RS
$D69C $F0:169C RW Enables 0 0 0 0 AIE PIE PWRIE ABE
$D69D $F0:169D RW Flags 0 0 0 0 AF PF PWRF BVF
$D69E $F0:169E RW Control 0 0 0 0 UTI STOP 12/24 DSE
$D69F $F0:169F RW Century 10s digit 1s digit
$D6A0: System Control Registers

Main page: Use the LEDs

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D6A0 $F0:16A0 W SYS0 RESET CAP_EN BUZZ L1 L0 SD_L PWR_L
R SYS0 SD_WP SD_CD BUZZ L1 L0 SD_L PWR_L
$D6A1 $F0:16A1 RW SYS1 L1_RATE L0_RATE SID_ST PSG_ST L1_MN L0_MN
$D6A7: F256k Series LEDs

Main page: Use the LEDs#LED_Color_Registers_on_the_K_and_K2

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D6A7 $F0:16A7 W Power LED color (BGR)
$D6AA $F0:16AA W Media LED color (BGR)
$D6AD $F0:16AD W Shift LED color (BGR)
$D6A7: Machine ID and FPGA Core Versions
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D6A7 $F0:16A7 R MID Machine ID
$D6A8 $F0:16A8 R PCBID0 ASCII character 0: "B" (See also $D6EB)
$D6A9 $F0:16A9 R PCBID1 ASCII character 1: "0"
$D6AA $F0:16AA R CHSV VICKY sub-version in BCD (16-bit)
$D6AC $F0:16AC R CHV VICKY version in BCD (16-bit)
$D6AE $F0:16AE R CHN VICKY number in BCD (16-bit)
$D6E0: Mouse Pointer Control
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D6E0 $F0:16E0 W MODE EN
$D6E2 $F0:16E2 RW X (16-bit)
$D6E4 $F0:16E4 RW Y (16-bit)
$D6E6 $F0:16E6 W PS2_BYTE_0
$D6E7 $F0:16E7 W PS2_BYTE_1
$D6E8 $F0:16E8 W PS2_BYTE_2
$D6EB: PCB Information
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D6EB $F0:16EB R PCBMA PCB Major Rev (ASCII)
$D6EC $F0:16EC R PCBMI PCB Minor Rev (ASCII)
$D6ED $F0:16ED R PCBD PCB Day (BCD)
$D6EE $F0:16EE R PCBM PCB Month (BCD)
$D6EF $F0:16EF R PCBY PCB Year (BCD)
$D700: VS1053b (F256 Gen 2 only)

Main page: Use the VS1053b chip

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D700 $F0:1700 SCI Control Control the flow of information
$D701 $F0:1701 SCI Address Select to which VS1053b address to write to
$D702 $F0:1702 SCI Data 1 First byte of data
$D703 $F0:1703 SCI Data 2 Second byte of data
$D704 $F0:1704 FIFO Count 1 First byte of the remaining byte count in the FIFO
$D705 $F0:1705 FIFO Count 2 Second byte of the remaining byte count in the FIFO
$D800: Text Mode CLUT
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D800 - $D83F $F0:1800 - $F0:183F W Text foreground colors (16 × BGRx)
$D840 - $D87F $F0:1840 - $F0:187f W Text background colors (16 × BGRx)
$D880: NES/SNES Gamepads

Main page: Use the SNES/NES controllers

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D880 $F0:1880 R NES_CTRL NES_TRIG DONE MODE NES_EN
W NES_CTRL NES_TRIG MODE NES_EN
$D884 $F0:1884 Pad 0
$D886 $F0:1886 Pad 1
$D888 $F0:1888 Pad 2
$D88A $F0:188A Pad 3
+0 Mode=0 A B SELECT START UP DOWN LEFT RIGHT
+0 Mode=1 B Y SELECT START UP DOWN LEFT RIGHT
+1 Mode=1 A X L R
$D900: Sprites
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$D900 - $DAFF $F0:1900 - $F0:1AFF 64 × 8-byte Sprite Registers
+0 W SIZE LAYER LUT ENABLE
SIZE 0: 32×32

1: 24×24

2: 16×16

3: 8×8

+1 W SRAM Address of sprite pixels (24-bit)
+4 W X position (16-bit)
+6 W Y position (16-bit)
$DB00: Moar system
$DB00: VIAs

See: Keyboard raw codes

* = F256k series only

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DB00* $F0:1B00* VIA1 Internal Keyboard VIA*
$DC00 $F0:1C00 VIA0 Atari joystick VIA
+0 RW IORB Port B Data
VIA0: Joystick 0, keyboard column 8*

VIA1: Keyboard columns 0-7*

+1 RW IORA Port A Data
VIA0: Joystick 1

VIA1: Keyboard row*

+2 RW DDRB Port B Data Direction Register
+3 RW DDRA Port A Data Direction Register
+4 RW T1C Timer 1 Counter (16-bit)
+6 RW T1L Timer 1 Latch (16-bit)
+8 RW T2C Timer 2 Counter (16-bit)
+A RW SDR Serial Data Registers
+B RW ACR T1_CTRL T2_CTRL SR_CTRL PBL_EN PAL_EN
+C RW PCR CB2_CTRL CB1_CTRL CA1_CTRL CA1_CTRL
+D RW IFR IRQF T1F T2F CB1F CB2F SRF CA1F CA2F
+E RW IER SET T1E T2E CB1E CB2E SRE CA1E CA2E
+F RW IORA2 Port A Data (no handshake)
VIA0 Joystick Bits
7 6 5 4 3 2 1 0
Keyboard column 8* Button 2 Button 1 Button 0 Right Left Down Up
VIA1 Internal Keyboard Matrix*
PB0 PB1 PB2 PB3 PB4 PB5 PB6 PB7 VIA0 PB7
PA0 Del Return Left F7 F1 F3 F5 Up Down
PA1 3 W A 4 Z S E LShift
PA2 5 R D 6 C F T X
PA3 7 Y G 8 B H U V
PA4 9 I J 0 M K O N
PA5 - P L Caps . ; [ ,
PA6 = ] ' Home RShift Alt Tab / Right
PA7 1 BS Ctrl 2 Space Foenix Q Run/Stop
$DD00: SD Card Controllers
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DD00 $F0:1D00 SD Card 0 (external)
$DD20 $F0:1D20 SD Card 1 (internal)
+0 RW SPI_BUSY SPI_CLK CS_EN
+1 RW SPI_DATA

SPI_CLK: 400MHz init clock when set, 12.5MHz standard clock when clear.

$DD40: F256K2 Case LCD Screen

Main page: Use the K2 LCD

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DD40 $F0:1D40 LCD_CMD_CMD Command
$DD41 $F0:1D41 LCD_CMD_DTA Data
$DD42 $F0:1D42 LCD_PIX_LO Green[2:0] Blue
$DD43 $F0:1D43 LCD_PIX_HI Red Green[5:3]
$DDA0: SAM2695 MIDI (F256 Gen 2 only)

Main page: Use the Sam2695 Dream MIDI chip

MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DDA0 $F0:1DA0 R MIDI_STATUS TX_EMPTY RX_FULL
$DDA1 $F0:1DA1 RW MIDI_FIFO_DATA_PORT Data
$DDA2 $F0:1DA2 MIDI_RXD_COUNT Rx FIFO Data count (12-bit)
$DDA4 $F0:1DA4 MIDI_TXD_COUNT Tx FIFO Data Count (12-bit)
$DDC0: Optical Keyboard Controller (F256K2 Only)
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DDC0 $F0:1DC0 OPT_KBD_DATA FIFO queue. Each event is two 8-bit reads from here
$DDC1 $F0:1DC1 R OPT_KBD_STATUS MECH FIFO_EMPTY
MECH = No optical keyboard if set
$DDC2 $F0:1DC2 OPT_KB_COUNT Number of events in optical keyboard queue (12-bit)
$DE00: Integer Math Coprocessor
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DE00 $F0:1E00 RW MULU_A Multiplication A (Unsigned 16-bit)
$DE02 $F0:1E02 RW MULU_B Multiplication B (Unsigned 16-bit)
$DE04 $F0:1E04 RW DIVU_DEN Division Denominator (Unsigned 16-bit)
$DE06 $F0:1E06 RW DIVU_NUM Division Numerator (Unsigned 16-bit)
$DE08 $F0:1E08 RW ADD_A Addition A (Unsigned 32-bit)
$DE0C $F0:1E0C RW ADD_B Addition B (Unsigned 32-bit)
$DE10 $F0:1E10 RW MULU Multiplication A×B Result (Unsigned 32-bit)
$DE14 $F0:1E14 RW QUOU Quotient of Num/Den (Unsigned 16-bit)
$DE16 $F0:1E16 RW REMU Remainder of Num/Den (Unsigned 16-bit)
$DE18 $F0:1E18 RW ADD_R Addition A+B Result (Unsigned 32-bit)

Multiplication, division, and addition operations are completely independent of each other. Results are available immediately.

$DF00: DMA Controller
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$DF00 $F0:1F00 RW START INT_EN FILL 2D ENABLE
$DF01 $F0:1F01 W Fill data byte
$DF04 $F0:1F04 RW Source SRAM Address (24-bit)
$DF08 $F0:1F08 RW Destination SRAM Address (24-bit)
$DF0C $F0:1F0C RW Count (24-bit, not 2D mode)
RW Width (16-bit, 2D mode)
$DF0E $F0:1F0E RW Height (16-bit, 2D mode)
$DF10 $F0:1F10 RW Source stride (16-bit, 2D mode)
$DF12 $F0:1F12 RW Destination stride (16-bit, 2D mode)

DMA only runs during VBlank, and halts the CPU to take over the entire bus. This runs at 100MHz, at 8 bits (gen 1) or 16 bits (gen 2) wide.

IO Page 1

$C000: Text Mode Font Sets
MMU Flat R/W Name Description
$C000 - $C7FF $F0:2000 - $F0:27FF RW Font set 0 (256 × 8-byte chars)
$C800 - $CFFF $F0:2800 - $F0:2FFF RW Font set 1 (256 × 8-byte chars)

Characters are 8×8 pixels. Each byte is an 8-pixel row of bits, with MSB at the left. 8 rows top to bottom.

$D000: Graphics CLUTs
MMU Flat R/W Name Description
$D000 - $D3FF $F0:3000 - $F0:33FF RW Graphics CLUT 0 (256 × BGRx)
$D400 - $D7FF $F0:3400 - $F0:37FF RW Graphics CLUT 1 (256 × BGRx)
$D800 - $DBFF $F0:3800 - $F0:3BFF RW Graphics CLUT 2 (256 × BGRx)
$DC00 - $DFFF $F0:3C00 - $F0:3FFF RW Graphics CLUT 3 (256 × BGRx)

IO Page 2

$C000: Text Screen Character Matrix
MMU Flat R/W Name Description
$C000 - $DFFF $F0:4000 - $F0:5FFF RW Text screen character matrix

1 byte per character, 40 or 80 characters per row, 25|30|50|60 rows in the matrix. Each character byte refers to an entry in the currently selected font set.

80×60 characters uses 4800 ($12C0) bytes, which is only a bit more than half the 8k allocation.

IO Page 3

$C000: Text Screen Color Matrix
MMU Flat R/W Name 7 6 5 4 3 2 1 0
$C000 - $DFFF $F0:6000 - $F0:7FFF RW Text screen color matrix
FG color (0-15) BG color (0-15)

Exact same layout as the character matrix. One color matrix byte associates to one character matrix byte at the same offset.