Memory Switches [NEC PC98]
PC98 has two configuration switches. The one is "Dip Switches" (ディップスイッチ) and the other is "Memory Switches" (メモリスイッチ). The Dip Switches can be set by real dip switches or the System Setup Menu. The Memory Switches can be set by utility commands in the N88-BASIC(86) and MS-DOS. Most configurations are effective only in N88-BASIC(86), but some of them are used by the boot loader.
The Memory Switches is stored on a volatile memory. If the internal rechargeable battery no longer works, its data will become corrupt with wrong data. Sometimes it prevents the system from booting. In this case, change the Dip Switches to initialize the Memory Switches.
Set the Memory Switches
There are three ways to set the Memory Switches.
Use a configuration utility in Disk BASIC
Boot from the Disk BASIC (N88-日本語BASIC(86)) and type "run "switch.n88"".
Use the "SWITCH" command on the MS-DOS.
You can only change settings related to the MS-DOS. See this.
Use the S command in the monitor mode of N88-BASIC(86)
Boot from the Disk BASIC (N88-日本語BASIC(86)) and type "mon" to enter the monitor mode. Then use "ssw" or "sswX" (X is a number you want to configure) command. Early 9801 models have the monitor mode in their built-in ROM BASIC.
Structure of the Memory Switches.
| SW | Bit | Description | Value | Meanings |
| SW1 N:A3FE2h H:E3FE2h |
7,6 | Length of stop bits | 11 | 2 bits |
| 10 | 1.5 bits | |||
| 01 | 1 bit | |||
| 5 | Parity Method | 1 | Even parity | |
| 0 | Odd parity | |||
| 4 | Parity checking | 1 | Enabled | |
| 0 | Disabled | |||
| 3,2 | Length of data bits | 11 | 8 bits | |
| 10 | 7 bits | |||
| 1 | Communication method (Terminal mode) |
1 | Half duplex | |
| 0 | Full duplex | |||
| 0 | X-parameters (XON/XOFF flow control) | 1 | Enabled | |
| 0 | Disabled | |||
| SW2 N:A3FE6h H:E3FE6h |
7 | S parameter (7-bit ANK bank switched by SI/SO) |
1 | Enabled |
| 0 | Disabled | |||
| 6 | Line-feed code when sending data | 1 | CR+LF | |
| 0 | CR | |||
| 5 | Line-feed Operation when receiving | 1 | CR+LF when received CR+LF CR when received CR |
|
| 0 | CR+LF when received CR | |||
| 4 | Kanji shift code | 1 | KI:1A70h KO:1A71h | |
| 0 | KI:1B4Bh KO:1B48h | |||
| 3,2,1,0 | Transfering speed | 1001 | 19200bps | |
| 1000 | 9600bps | |||
| 0111 | 4800bps | |||
| 0110 | 2400bps | |||
| 0101 | 1200bps | |||
| 0100 | 600bps | |||
| 0011 | 300bps | |||
| 0010 | 150bps | |||
| 0001 | 75bps | |||
| SW3 N:A3FEAh H:E3FEAh |
7 | Operation when received DEL code (Editor mode) |
1 | NUL |
| 0 | DEL | |||
| 7 | Operation when received DEL code (Terminal mode) |
1 | NUL | |
| 0 | BS | |||
| 6 | Text color | 1 | Green | |
| 0 | White | |||
| 5 | Clock speed of V30 Co-processor | 1 | 8 MHz | |
| 0 | 5 or 10 MHz | |||
| 4 | Co-processor for V30 | 1 | Use | |
| 0 | Not use | |||
| 3 | Co-processor for 8086,80286,386 | 1 | Use | |
| 0 | Not use | |||
| 2,1,0 | Size of the conventional memory | 101 | 768KB(only in Hi-reso mode) | |
| 100 | 640KB | |||
| 011 | 512KB | |||
| 010 | 384KB | |||
| 001 | 256KB | |||
| 000 | 128KB | |||
| SW4 N:A3FEEh H:E3FEEh |
7 | Expansion ROM(CE000h - CFFFFh) | 1 | Enabled |
| 0 | Disabled | |||
| 6 | Expansion ROM(CA000h - CBFFFh) | 1 | Enabled | |
| 0 | Disabled | |||
| 5 | Expansion ROM(D4000h - D5FFFh) (GP-IB Board BIOS) |
1 | Enabled | |
| 0 | Disabled | |||
| 4 | Expansion ROM(D0000h - D3FFFh) (RS-232C Expansion Board BIOS) |
1 | Enabled | |
| 0 | Disabled | |||
| 3 | Expansion ROM(CC000h - CFFFFh) (Sound Board BIOS) |
1 | Enabled | |
| 0 | Disabled | |||
| 2 | Expansion ROM(C8000h - C9FFFh) | 1 | Enabled | |
| 0 | Disabled | |||
| 1 | (Reserved) | 0 | Always "0" | |
| 0 | (Reserved) | 0 | Always "0" | |
| SW5 N:A3FF2h H:E3FF2h |
7,6,5,4 | Select a boot device | 1100 | SCSI HDD #1 |
| 1011 | HDD #2 | |||
| 1010 | HDD #1 | |||
| 1000 | ROM BASIC | |||
| 0110 | MO | |||
| 0100 | 1MB FDD | |||
| 0010 | 640KB FDD | |||
| 0000 | Default | |||
| Others | ROM BASIC (Built-in BASIC) | |||
| 3 | Color of the Screen Hardware Copy | 1 | Color | |
| 0 | Monochrome | |||
| 2 | Use HDD User ID | 1 | Enabled | |
| 0 | Disabled | |||
| 1 | Assign device names to HDDs first | 1 | Enabled | |
| 0 | Disabled | |||
| 0 | PC-PR201 series printer | 1 | Enabled | |
| 0 | Disabled | |||
| SW6 N:A3FF6h |
7 | (Reserved) | 0 | Always "0" |
| 6 | (Reserved) | 0 | Always "0" | |
| 5 | Use a modem - NCU control | 1 | Enabled | |
| 0 | Disabled | |||
| 4 | Use the extended screen copy | 1 | Enabled | |
| 0 | Disabled | |||
| 3 | Use the monitor mode | 1 | Enabled | |
| 0 | Disabled | |||
| 2 | (Reserved) | 0 | Always "0" | |
| 1 | (Reserved) | 0 | Always "0" | |
| 0 | (Reserved) | 0 | Always "0" |
Default : 48-05-04-00-01-00