Copyright(C) 1994,1995,1996,1997 Terumasa KODAKA , Takeshi KONO
■Software DIP Switches
Target Models with software DIP switches
98NOTE■[Excluding PC-9801N, NS, NV, NS/E, and NC]
PC-9801UR, UF, US, FA, FX, FS, BA, BX, BA2, BS2, BX2, BA3, BX3, and BX4
PC-9821■[Excluding PC-9821Ap, As, and Ae]
Explanation o I/O 841E to 8F1Eh are software DIP switches used for hardware
settings, saving settings, and other purposes for various setting items in the
system setup menu.
o Software DIP switches are composed of a front bank and a back bank, and each
I/O port has two software DIP switches on the front and back.
The method of bank selection may differ slightly depending on the model, so in
order to reliably access the software DIP switches, it is necessary to
identify the model and select the bank selection method according to each model.
Table: Bank selection method for each model
------------------------------------------------+----------------------+--------------------
Model name | Front bank selection | Back bank selection
------------------------------------------------+----------------------+--------------------
PC-9801UF, UR, US, FA, FX, FS | No bank (front bank only)
------------------------------------------------+----------------------+--------------------
PC-9801NS/T, NL, NS/L, NA, NL/R | |
PC-9801BA, BX, PC-9821 first generation, Ce | out 00F6h, A0h | out 00F6h, E0h
------------------------------------------------+----------------------+--------------------
PC-9801NS/R, P, NX/C | out F0F6h, A0h | out F0F6h, E0h
------------------------------------------------+----------------------+--------------------
PC-9801NS/A, NL/A | |
PC-9821Ne･Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･ | |
Ne3･Nd2･Na7･Nx･Lt2 | out 8F1Fh,A0h | out 8F1Fh,E0h
------------------------------------------------+----------------------+--------------------
PC-9801BA2･BS2･BX2･BA3･BX3･BX4 | |
PC-9821Af･Ap2･As2･Bp･Bs･Be･Bf･Ts･Cs2･ | |
Ce2･An･Xt･Xa･Xf･Xn･Xp･Xs･Xe･Cf･Cx･Cb･ | |
Ap3･As3･Xa16･Xa13･Xa12･Xa10･Xa9･Xa7･Xa7e | |
Xt16, Xt13, Xv13, Xb10, Xe10 | |
V10, V7, Cx2, Cb2, Cx3, Cb3 | out 8F1Fh,80h | out 8F1Fh,C0h
------------------------------------------------+----------------------+--------------------
o PC-9801DA, DX, DS, and CS also use the I/O space from I/O 841E to 8F1Eh for
software dip switch settings, but the bit assignments are different from those
of other models.
Related I/O 00F6h - A0h,E0h
I/O F0F6h - A0h,E0h
I/O 8F1Fh - 80h,C0h
I/O 8F1Fh - A0h,E0h
I/O 841Eh (table)
Name Software DIP switch
Undocumented
Function
[READ/WRITE]
bit 7: GRPH mode
1 = Extended mode
0 = Basic mode
bit 6: HDD sector length
1 = 512 bytes/sector
0 = 256 bytes/sector
bit 5,4: RS-232C transmission method
11b = Asynchronous (default)
10b = ST2 synchronous
01b = Synchronous clock
00b = BCI synchronous
bit 3: Drive number of built-in FDD drive
1 = Built-in drive is 1 or 2
0 = Built-in drive is 3 or 4
bit 2: DIS-SW 1-3
1 = Plasma display mode
0 = CRT mode
* Undocumented in 98NOTE series.
In the 98 Note menu, DIP-SW 1-3 is always set to OFF, but it can be changed.
bit 1: Disconnect sound BIOS ■ [PC-9801US, PC-9821Af, Ap2, As2, Cs2, Ce2, An, Ap3, As3, Cb2, Cx2, Na7, Nx]
1 = Disconnect
0 = Do not disconnect
bit 0: odd parity
* Odd parity of this byte
Explanation o Configure various settings.
Related 0000:0457h
0000:05B0h
I/O 0031h
I/O 006Ah - 40h,41h
I/O 7FDDh bit 1,0
I/O 851Eh (table)
Name Software DIP switch
Undocumented
Function
[WRITE]
bit 7: GDC clock frequency
1 = 2.5MHz
0 = 5.0MHz
bit 6: Use Vf key ■ [PC-9821Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2･Na7･Nx, other than PC-9801NL/A]
1 = Yes
0 = No
bit 5: Internal HDD disconnection
1 = Do not disconnect
0 = Disconnect
bit 4: odd parity
* Odd parity of this byte
bit 3: Number of text screen lines
1 = 20 lines
0 = 25 lines
bit 2: Number of text screen columns
1 = 40 lines
0 = 80 lines
bit 1: Terminal mode setting
1 = Start BASIC
0 = Start terminal mode
bit 0: BASIC mode
1 = Start BASIC mode
0 = Start N-BASIC
* No actual meaning
[READ]
bit 4: odd parity
* Odd parity of this byte
Explanation o Bits other than 4 set the value read from PORT A of system port PIO 8255.
o I/O 871Eh bit 5 is used to set the value read from I/O 0031h bit 4.
Related I/O 0031h
I/O 871Eh bit 5
I/O 861Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity for this byte
bit 6: Reserved
* Normally set to 0
bit 5: Main memory capacity
1 = 640Kbytes
0 = 512Kbytes
bit 4: DMA compatible/high-speed mode switch
1 = compatible mode
0 = high-speed mode
bit 3: Floppy motor control
1 = Yes
0 = No
bit 2: Dedicated SCSI DMA channel selection ■[PC-9821Ce･Af･Ap2･As2･An･Ap3･As3]
1 = DMA ch0 selected
0 = DMA ch1 selected
* Sets the DMA channel used by the SCSI board installed in the SCSI dedicated slot
bit 1: FDD fixed mode operation mode
1 = 640KB mode
0 = 1MB mode
bit 0: FDD interface mode
1 = automatic switching mode
0 = fixed mode
Explanation
Related I/O 0031h
I/O 00F4h
I/O 0CC4h bit 1,0
I/O 871Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
bit 6: Unknown ■ [98NOTE]
bit 5: Initialize memory switch
1 = Yes
0 = No
* Sets the value read by I/O 0031h bit 4
bit 4: Use memory for RAM drive
1 = Use as RAM drive
0 = Use as protected memory
bit 3,2: BEEP volume ■ [98NOTE PC-9821Bp Bs Be Bf Ts Xe Xe10 PC-9801BA2 BS2 BX2 BA3 BX3 BX4]
11b = Large
10b = Medium
01b = Small
00b = Silent
bit 1: LCD gradation (DIP-SW 3-3) ■ [98NOTE monochrome LCD]
1 = Use monochrome LCD with 8 gradations
0 = Use monochrome LCD with 2 gradations
* In the NOTE menu, DIP-SW 3-3 is always set to OFF, but it can actually be changed.
bit 0: LCD inversion (DIP-SW 3-4) ■ [98NOTE monochrome LCD]
1 = Reverse
0 = Normal
bit 0: Unknown ■ [PC-9821Cf/Cx/Cb]
1 = Without IDE
0 = With IDE
Explanation
Related I/O 851Eh bit 7-5,3-0
I/O 0031h bit 4
I/O 881Eh (table)
Name Software DIP switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity for this byte
bit 6: Use of Vf key (DIP SW2-7) ■ [PC-9821Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Na7･Nx, other than PC-9801NL/A]
1 = Yes
0 = No
bit 6: Use of sound function ■ [PC-9821Np･Nf]
1 = Use
0 = Do not use
bit 5: Use of sound function ■ [PC-9821 first generation･Ce･Af･Ap2･As2･Cs2･Ce2･An
Xt, Xa, Xf, Xn, Xp, Xs, Ap3, As3, Xa10, Xa9, Xa7, Xe10/C4
Na7, Nx, Na9, Na12]
1 = Use
0 = Disable
bit 4,3: EMS function■[PC-9821Np, Ns, Ne2, Nd, Es, Ld, Lt, Nf, Nm, Ne3, Nd2,
Na7, Nx, PC-9801NL/A excepted]
11b = Disable
10b = Sound
01b = Network
00b = Use
bit 4,3: Sound interrupt channel■[PC-9821Np, Nf, Na7, Nx]
00b = INT0
01b = INT1
10b = INT41
11b = INT5
bit 2: Keyboard selection ■ [PC-9821Np, Ns, Nf, Na7, Nx]
1 = Select built-in keyboard
0 = Select external keyboard
bit 1: Resume ON/OFF
1 = Yes
0 = No
bit 0: Use of RS-232C ■ [PC-9801NS/T, NL, NS/L, NA, NS/R, PC-9821Ne]
1 = Not used
0 = Used
bit 0: 16MB space control ■ [PC-9801NS/A, NL/A, PC-9821Np, Ns, Ne2, Nd, Es,
Ld, Lt, Nf, Nm, Ne3, Nd2, Na7, Nx]
1 = Memory to be disconnected (not used by the system) is linear
0 = Memory to be disconnected (used by the system) is divided
Related I/O 043Bh bit 2
Explanation o Holds various settings.
Related 0000:0400h bit 5
I/O 08F0h,08F2h - 0056h bit 0
I/O 0900h,0906h - 0014h bit 1
I/O 0F40h bit 5-3■[PC-9821Np･Nf･Na7･Nx]
I/O 891Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: Buzzer stop
1 = No
0 = Yes
bit 6,5: Dial mode
11b = 20PPS
10b = 10PPS
00b = Tone
bit 4: Loopback test
1 = No
0 = Yes
bit 3,2: Communication speed
00b = 2400bps
01b = 1200bps
10b = 300bps
11b = AUTO
bit 1,0: Modem mode
00b = AUTO
01b = CALL
10b = ANS
Description o Holds various settings for the 98NOTE built-in modem.
Related I/O 6E8Eh
I/O 8A1Eh
I/O 8A1Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: Use modem
1 = Yes
0 = No
bit 6: Parity
* Parity that combines I/O 891Eh and I/O 8A1Eh to make ODD
bit 5: Loss of carrier disconnect
1 = No
0 = Yes
bit 4: Select CI option
1 = No
0 = Yes
bit 3: Select CD option
1 = No
0 = Yes
bit 2: Confirm answer tone
1 = No
0 = Yes
bit 1: Send answer tone
1 = No
0 = Yes
bit 0: Automatic answer
1 = No
0 = Yes
Explanation o Holds various settings for the 98NOTE built-in modem.
Related I/O 7E8Eh
I/O 891Eh
I/O 8B1Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity for this byte
bit 6: Use of ROM BASIC ■ [PC-9801NS/R･NX/C･BX･BA, PC-9821Ne]
1 = Yes
0 = No
bit 6: Interrupt timer status of calendar clock IC for timer ■ [PC-9801P]
1 = Calendar clock IC interrupt timer start
0 = Calendar clock IC interrupt timer stop
bit 6: Unknown ■ [PC-9821Af･Ap2･As2･Bp･Bs･Be･Bf･Ce2･Cs2･TS, PC-9801BA2･BS2･BX2･BA3･BX3･BX4]
bit 6: Boot mode ■ [PC-9821Cf/Cx/Cb/Cx2/Cb2]
1 = Text boot mode
0 = Graphics boot mode
* Sets the boot mode for the 98MULTi CanBe series.
Related F8E8:0005h bit 6
bit 5-2: Time until standby mode is entered■[98NOTE]
1111b = Do not use standby mode
1110b = 60 minutes
1101b = 55 minutes
1100b = 50 minutes
1011b = 45 minutes
1010b = 40 minutes
1001b = 35 minutes
1000b = 30 minutes
0111b = 25 minutes
0110b = 20 minutes
0101b = 15 minutes
0100b = 10 minutes
0011b = 6 minutes
0010b = 3 minutes
0001b = 2 minutes
0000b = 1 minute
bit 1,0: Internal modem settings
11b = Half duplex
10b = AT
01b = V25bis
00b = Not used
bit 0: Use of infrared interface ■ [PC-9821Cb2･Cx2･98NOTE]
1 = Use
0 = Not use
Explanation
Related I/O 08F0h,08F2h - 0052h
0000:045Dh bit 7
0000:045Dh bit 6
I/O 8C1Eh (Table)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
bit 6,5: VRAM window address ■[PC-9821Np･Ns･Ne2･Nd･Es･Nf]
11b = F40000-F4FFFFh
10b = F60000-F6FFFFh
01b = F20000-F2FFFFh
00b = F00000-F0FFFFh
Related I/O 0FAAh,0FABh - 01h
bit 6: 98 Slide Pad Operation ■[PC-9821Na7･Nx]
1 = No tap/drag operation
0 = Tap/drag operation
bit 5,4: Mouse emulation mode ■ [PC-9801P]
11b = No mouse emulation
10b = Indirect mode
01b = Direct mode
00b = Undefined
bit 4: Pointing device specification ■ [PC-9821Ne･Np･Ns･Ne2･Es･Nd･Ld･Lt･Nf･Nm･Ne3･Nd2, PC-9801NL/A]
1 = Thumbball/98Slidepad
0 = Mouse
Related I/O 6B8Eh bit 3 ■ [PC-9821Ne]
I/O 4C8Eh bit 0 ■ [PC-9821Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2, PC-9801NL/A]
bit 4: Unknown ■ [PC-9801NS/R･NX/C･NS/A･NL/R, PC-9821Ne]
bit 3-0: Time until auto power off
1111b = No auto power off
1110b = 60 minutes
1101b = 55 minutes
1100b = 50 minutes
1011b = 45 minutes
1010b = 40 minutes
1001b = 35 minutes
1000b = 30 minutes
0111b = 25 minutes
0110b = 20 minutes
0101b = 15 minutes
0100b = 10 minutes
0011b = 6 minutes
0010b = 3 minutes
0001b = 2 minutes
0000b = 1 minute
Explanation o Holds various settings.
Related INT 1Fh - Function 9B08h
I/O 08F0h,08F2h - 0050h
I/O 8D1Eh (table)
Name Software DIP switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
bit 6: Use of RAM drive memory
1 = Not used
0 = Used
bit 5: NOTEMENU, PENMENU patch data existence flag
1 = Exists
0 = Does not exist
bit 4: Write protection of RAM drive
1 = Not used
0 = Enabled
bit 3: Setting of first drive
1 = FDD
0 = RAM drive
bit 2,1: Setting of system startup device
11b = FDD priority
10b = RAM
01b = FDD
00b = Undefined
bit 0: Usage of RAM drive memory
1 = Used as RAM drive
0 = Used or not used as protected memory
Explanation
Related 0000:0488h
0000:048Eh
I/O 8E1Eh (table)
Name Software DIP switch
Undocumented
Target 98NOTE
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity for this byte
bit 6: Battery warning beep suppression■[PC-9821Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2･Na7･Nx,PC-9801NL/A]
1 = Warning beep
0 = Warning beep not sounded
bit 5: Card related unknown
bit 4: CPU mode■[PC-9801NA･NS/R･NX/C･NL/A, PC-9821Ne･Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2]
1 = Middle,Low mode
0 = High mode
bit 4: Use of calendar clock IC for timer ■ [PC-9801P]
1 = Use
0 = Do not use
bit 3: Unknown
bit 2: CG related (backup of software DIPSW)
1 = DIP switch mode
0 = Normal mode
bit 1: Linkage of LCD panel and power button ■ [PC-9801NS/T･NS/L･NA･NS/R･NX/C･NS/A･NL/R･NL/A, PC-9821Ne･Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2･Na7･Nx]
1 = Yes
0 = No
bit 1: Selection of calendar clock IC ■ [PC-9801P]
1 = Select calendar clock IC for timer
0 = Select normal calendar clock IC
bit 0: [NUM] key usage ■ [PC-9801NS/T･NS/L･NA･NS/R･NX/C･NS/A･NL/R･NL/A
PC-9821Ne･Np･Ns･Ne2･Nd･Es･Ld･Lt･Nf･Nm･Ne3･Nd2]
1 = Do not use
0 = Use
Explanation
Related
I/O 8E1Eh (table)
Name Software DIP switch
Undocumented
Target PC-9821Ce, Af, Ap2, As2, Bp, Bs, Be, Bf, Cs2, Ce2, Ts, An, Xt, Xa, Xp, Xn, Xp, Xs, Xe, Xf, Ap3, As3, Cf, Cx, Cb, Xa10, Xa9, Xa7, Xe10, Cx2, Cb2
PC-9801BA2, BS2, BX2, BA3, BX3, BX4
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
bit 6: Unknown
bit 5: Unknown
bit 4: CPU mode (Low mode flag)
1 = Low
0 = Middle, High mode
bit 3: Unknown
bit 2: CG related (backup of software DIPSW)
1 = DIP switch mode
0 = Normal mode
bit 1,0: Unknown ■ [PC-9821Af]
01b = High mode
00b = Middle mode
10b = Low mode
bit 1: Unknown ■ [PC-9821Ap2･As2]
bit 0: 2nd cache control ■ [PC-9821Ap2･As2･Bp･Bf･An･Ap3･As3]
1 = 2nd cache disabled
0 = 2nd cache enabled
Explanation
Related I/O 063Dh
I/O 8F1Eh (table)
Name Software DIP switch
Undocumented
Target 98NOTE, PC-9801BA･BX
Function
[READ/WRITE]
bit 7: GRPH mode
1 = Extended mode
0 = Basic mode
bit 6: Main memory capacity
1 = 640KB
0 = 512KB
bit 5,4: RS-232C transmission method
11b = Asynchronous
10b = ST2 synchronous
01b = Synchronous clock
00b = BCI synchronous
bit 3: Drive number of built-in FDD drive
1 = Built-in drive is 1 or 2
0 = Built-in drive is 3 or 4
bit 2: CPU mode (Low mode flag)
1 = V30 mode ■ [PC-9801NS/T･NS/L]
0 = 386SL(98) mode ■ [PC-9801NS/T]
0 = 386SX mode ■ [PC-9801NS/L]
1 = Low mode ■ [PC-9801NA and later]
0 = High, Middle mode ■ [PC-9801NA and later]
bit 1: GDC clock frequency
1 = GDC 2.5MHz
0 = GDC 5MHz
bit 0: odd parity ■
* Odd parity of this byte
Explanation o Holds various settings.
Related
I/O 8F1Eh (table)
Name Software DIP switch
Undocumented
Target PC-9821Ce, Af, Ap2, As2, Bp, Bs, Be, Bf, Cs2, Ce2, Ts, An, Xt, Xa, Xp,
Xn, Xp, Xs, Xe, Xf, Ap3, As3, Cf, Cx, Cb, Xa10, Xa9, Xa7, Xe10, Cx2, Cb2
PC-9801BA2, BS2, BX2, BA3, BX3, BX4
Function
[READ/WRITE]
bit 7: odd parity
bit 6: Use disk connection unit
1 = Yes
0 = No
bit 5: Use ROM BASIC
1 = Yes
0 = No
bit 4: Unknown ■ [PC-9821An]
bit 3: Drive number of the built-in FDD drive
1 = Built-in drive is 1 or 2
0 = Built-in drive is 3 or 4
bit 2: CPU mode (Low, Middle mode flag)
1 = Low, Middle mode
0 = High mode
bit 1: Use of line adapter ■ [PC-9821Af, Ap2, As2, An, Ap3, As3]
1 = Yes
0 = No
bit 0: 16MB space control ■ [PC-9821Af, Ap, As2, Bp, Bs, Be, Bf, Cs2, Ce2, Ts, An
Xt, Xa, Xf, Xn, Xp, Xs, Xe, Cf, Cx, Cb, Ap3, As3,
Xa10, Xa9, Xa7, Xe10, Cx2, Cb2
PC-9801BA2･BS2･BX2･BA3･BX3･BX4]
1 = Memory to be disconnected (not used by the system) is linear
0 = Memory to be kept disconnected (used by the system) is divided
Related I/O 043Bh bit 2
Explanation o Holds various settings.
Related 0000:045Dh
I/O 841Eh (back)
Name Software DIP switch
Undocumented
Target PC-9821Ce, Af, Ap2, As2, Bp, Bs, Be, Bf, Cs2, Ce2, Ts, An, Xt, Xa, Xp,
Xn, Xp, Xs, Xe, Xf, Ap3, As3, Cf, Cx, Cb, Xa10, Xa9, Xa7, Xe10, Cx2, Cb2
PC-9801BA2, BS2, BX2, BA3, BX3, BX4
Function
[READ/WRITE]
bit 7: odd parity
* odd parity of this byte
bit 6-4: Unknown ■ [PC-9801NL/A]
Related I/O 698Eh
I/O 08F0h, 08F2h - 0056h
I/O 0900h,0906h - 0014h bit 1
bit 3-0: Time until HDD motor stops
1111b = Do not stop HDD motor
1110b = 60 minutes
1101b = 55 minutes
1100b = 50 minutes
1011b = 45 minutes
1010b = 40 minutes
1001b = 35 minutes
1000b = 30 minutes
0111b = 25 minutes
0110b = 20 minutes
0101b = 15 minutes
0100b = 10 minutes
0011b = 6 minutes
0010b = 3 minutes
0001b = 2 minutes
0000b = 1 minute
Description o Sets the time until the HDD spindle motor stops.
Related 0000:0598h
0000:05B1h
0000:059Ah
■[PC-9821Ap2･As2･Bp･Bs･Be･Bf･Cs2･Ce2･Ts･An･Xa･Xn･Xp･Xs･Xe･Xf･Cf･Cx･Cb･Ap3･As3,PC-9801BA2･BS2･BX2･BA3･BX3]
INT 17h I/O 047Bh
I/O 851Eh (back)
Name Software DIP switch
Undocumented
Target PC-9801NS/T･NS/L･NS/R･P･NL/R
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
bit 3-0: Time until power saving
1111b = Do not use power saving
1110b = 60 seconds
1101b = 55 seconds
1100b = 50 seconds
1011b = 45 seconds
1010b = 40 seconds
1001b = 35 seconds
1000b = 30 seconds
0111b = 25 seconds
0110b = 20 seconds
0101b = 15 seconds
0100b = 10 seconds
0011b = 6 seconds
0010b = 3 seconds
0001b = 2 seconds
0000b = 1 second
Description o Sets the time before entering power saving mode.
Related I/O 08F0h,08F2h - 0050h
0000:045Ch
I/O 861Eh(back)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 0: Unknown■[PC-9801NS/T]
Explanation o Details unknown
I/O 871Eh(back),881Eh(back),891Eh(back),8A1Eh(back),8B1Eh(back),8C1Eh(back),8D1Eh(back)
Name Software DIP Switch
Undocumented
Function
[READ/WRITE]
bit 7: odd parity
* Odd parity of this byte
Explanation o Unused
I/O 8E1Eh (back)
Name Software DIP switch
Undocumented
Target PC-9801NS/T･NL･NS/L･NA･NS/R
Function
[READ/WRITE]
bit 7-5: Interrupt address used by card B
111b = No interrupt
110b = INT6
101b = INT5
100b = INT4
011b = INT3
010b = INT2
001b = INT1
000b = INT0
bit 4-2: Interrupt address used by card A
111b = No interrupt
110b = INT6
101b = INT5
100b = INT4
011b = INT3
010b = INT2
001b = INT1
000b = INT0
bit 1,0: DMA channel used by the card
11b = CH3
10b = DMA not used
01b = Unknown (undefined?)
00b = CH0
Explanation o Sets the interrupt and DMA channel used by the card.
Related I/O 6F8Eh
I/O FC8Eh
I/O 8F1Eh (back)
Name Software DIP switch
Undocumented
Target PC-9801NS/T･NL･NS/L･NA･NS/R
Function
[READ/WRITE]
bit 7〜0: Card switch information
Explanation o Stores the value to be output as the card switch.
Related I/O 0F8Eh