Copyright(C) 1994,1995,1996,1997 Terumasa KODAKA , Takeshi KONO
■Keyboard interface
Target Normal, high resolution, PC-98LT・HA
Chip 8251A (equivalent)
Explanation o In the PC-9800 series, keyboard key input information is sent to the main unit as a serial signal (fixed at 19200bps).
When the keyboard I/F 8251A (equivalent) receives key input information, it generates an INT 09h interrupt and notifies
software (BIOS, etc.) of the key input.
o Even with models that have an integrated keyboard and main body, such as 98NOTE and PC-98LT/HA, the keyboard and
keyboard I/F communicate serially, just like desktop machines.
u With the 98NOTE series, it is possible to connect a full keyboard to the numeric keypad connector.
o In the PC-9800 series, the 8251 TXD signal line is connected to RST# (keyboard connector pin 1) and was originally used
to reset the keyboard, but the new keyboard uses this to send commands. It started to be done.
o Models with new keyboards can send commands to the keyboard. You can obtain the lock status of the [CAPS], [Kana], and
[NUM] keys, control the lock status, and change the key repeat interval.
o The following keyboards are valid for the PC-9800 series.
----------------------------+---------------------------------------------
Old keyboard |
+---------------------------+---------------------------------------------
| PC-98LT | [BS],[ROLL UP],[ROLL DOWN],[DEL],[HELP],[COPY]
| | There is no key, but you can use the following operation instead.
| | [BS],[DEL] =[DEL BS]
| | [HELP] =[CTRL]+[SHIFT]+[H]
| | [ROLL UP] =[CTRL]+[SHIFT]+[↑]
| | [ROLL DOWN]=[CTRL]+[SHIFT]+[↓]
| | [COPY] =[CTRL]+[SHIFT]+[P]
+---------------------------+---------------------------------------------
| High resolution | PC-98XA・XL・XL^2
+---------------------------+---------------------------------------------
| No NFER | PC-9801 first generation・E・F・M
+---------------------------+---------------------------------------------
| Other | Other than PC-9801 first generation/E/F/M
-+---------------------------+---------------------------------------------
New keyboard |
+---------------------------+---------------------------------------------
| 98NOTE | 98NOTE series
+---------------------------+---------------------------------------------
| PC-9801-98 | Rakuraku Keyboard
+---------------------------+---------------------------------------------
| PC-9801-106 | 98 standard keyboard (Windows key, no application key)
+---------------------------+---------------------------------------------
| PC-9801-114 | PC-PTOS keyboard
+---------------------------+---------------------------------------------
| PC-9801-115 | Bungo DP Keyboard
+---------------------------+---------------------------------------------
| PC-9801-116 | 106 keyboard
+---------------------------+---------------------------------------------
| PC-9801-119 | 98 standard keyboard (with Windows key and application key)
+---------------------------+---------------------------------------------
| Others | PC-9801-106, PC-9801T-03 equivalent
-+---------------------------+---------------------------------------------
Related I/O 0000h bit 1
INT 18h - Function 00~09h
INT 09h (external interrupt)
0000:0502～053Ah
I/O 0041h
Name Keyboard interface
Function
[READ] Read received data
bit 7～0: Make/break code, status
00~7Fh=Make code
80~FFh=break code
FAh=ACK
FCh=NACK
[WRITE] Write transmit data
bit 7～0: Down command
----------------+---------------------------------------------------
Command | Content
----------------+---------------------------------------------------
95h | Extended key settings■[PC-9801-98･119](Undocumented)
| * Output parameters in 2nd byte
| bit 7～0:
| 00h=normal
| 03h=Windows key, application key enabled
| ■[PC-9801-119]
----------------+---------------------------------------------------
96h | Mode identification■[PC-9801-98](Undocumented)
| * A0h,86h is returned in automatic conversion mode
| * A0h,85h is returned in normal mode
----------------+---------------------------------------------------
99h | Undocumented
| * FBh is returned
----------------+---------------------------------------------------
9Ch | Keyboard repeat speed setting (Undocumented)
| * Output parameters in 2nd byte
| bit 7: Unused
| bit 6,5: Delay
| 11b=1000ms
| 10b=500ms
| 01b=500ms (default)
| 00b=250ms
| bit 4～0: Repeat speed
| 11111b=lowest speed
| 00001b= Maximum speed (default)
----------------+---------------------------------------------------
9Dh | Unknown■[PC-9801NS/T](Undocumented)
| * Output parameters in 2nd byte
| 00h=Unknown
| 01h=Unknown
----------------+---------------------------------------------------
9Dh | Keyboard LED reading (Undocumented)
| * Send 60h to 2nd byte
| * LED status is sent in the following format
| bit 7~4: Unused
| bit 3: [Kana] LED
| bit 2: [CAPS] LED
| bit 0: [NUM] LED
| 1=ON
| 0=OFF
----------------+---------------------------------------------------
9Dh | Keyboard LED settings
| * Output parameters in 2nd byte
| bit 7~4: always 0111b
| bit 3: [Kana] LED
| bit 2: [CAPS] LED
| bit 0: [NUM] LED (Undocumented)
| 1=ON
| 0=OFF
----------------+---------------------------------------------------
9Eh | Undocumented
----------------+---------------------------------------------------
9Fh | Keyboard type identification
| * New keyboard returns A0h,80h
----------------+---------------------------------------------------
Description o Get the make/break code from the keyboard.
o Issue a down command to the keyboard.
Related I/O 0041h
I/O 0043h
Name Keyboard interface
Function
[READ] ■Meaning of bits when reading status
bit 7: DSR input terminal
1=HIGH level
0=LOW level
* Indicates the status of keyboard connector pin 6. (Undocumented)
bit 6: SYNC/BRK
1=Break detection
0=None
* Does not occur as long as a regular handshake with the keyboard is performed.
bit 5: Framing error (FE) detection
1=Yes
0=None
bit 4: Overrun error (OE) detection
1=Yes
0=None
* Does not occur as long as a regular handshake with the keyboard is performed.
bit 3: Parity error (PE) detection
1=Yes
0=None
bit 2: TxEMP (end of transmission)
bit 1: RxRDY (data reception)
bit 0: TxRDY (transmission possible)
[WRITE] ■Meaning of bits when writing command word
bit 7: Enterhunt phase
* Keyboard I/F is not used because it is asynchronous communication. Set to 0.
bit 6: 8251A reset
1=Do
0=No
bit 5: RTS terminal control
1=RDY# signal line is always inactive
0=RDY# signal line follows the state of RxRDY
* The keyboard I/F controls the operation of the RDY# signal line (keyboard connector pin 3).
bit 4: Clear error flag
1=Clear FE, OE, PE of 8251A
0=Do not clear error
bit 3: TxDATA break transmission
1=Set RST# signal line to LOW level
0=RST# signal line to HIGH level
* The keyboard I/F controls the operation of the RST# signal line (keyboard connector pin 1).
When the RST# signal line is set to LOW level for a period of 13μs or more, the CPU in the keyboard is reset.
bit 2: Receive permission
1=Receive data from keyboard
0=Do not receive data from keyboard
bit 1: DTR signal
1=RTY# signal to HIGH level
0=RTY# signal to LOW level
* The keyboard I/F controls the operation of the RTY# signal line (keyboard connector pin 5). Usually HIGH. When LOW, requests the keyboard to resend data.
bit 0: Send permission
1=Send data from RST# signal line
0=Do not send data from RST# signal line
* The keyboard I/F uses the RST# signal line when issuing down commands to the keyboard. Set to 1 when sending a command.
[WRITE] ■Meaning of bits during mode write
bit 7,6: ST2,ST1 (number of transmission stop bits)
Set 01b (1 bit)
bit 5,4: P1,P0 (parity generation/check)
Set 01b (odd parity)
bit 3,2: L1,L0 (character length)
Set 11b (8 bit)
bit 1,0: B1,B0 (baud rate)
Set 10b (16x clock)
Description o Sets the mode of the 8251 equivalent used for the keyboard interface.
Related I/O 0043h