Copyright(C) 1994 Terumasa KODAKA , Takeshi KONO
■RS-232C BIOS
INT 19h - Function 00h (BIOS)
Classification RS-232C BIOS
Name Initialize RS-232C BIOS (single mode)
Target Normal, Hi-Res, PC-98LT/HA
Input AH=00h: Specify channel 0 (built-in RS-232C)
10h: Specify channel 1 (extended RS-232C interface) ■ [Hi-Res]
20h: Specify channel 2 (extended RS-232C interface) ■ [Hi-Res]
AL=Transfer speed ■ [Only channel 0 is valid]
00h = 75bps
01h = 150bps
02h = 300bps
03h = 600bps
04h = 1200bps
05h = 2400bps
06h = 4800bps
07h = 9600bps
08h = 19200bps■[Only for devices that support 19200bps]
* If an unsupported value is specified, it will be set to 1200bps
BH=Timeout time when sending (unit: 500ms)
* Range is 01-FFh. If 00h is specified, the default value (02h) will be used
BL=Timeout time when receiving (unit: 500ms)
* Range is 01-FFh. Specifying 00h will set it to the default value
(1Eh for normal mode, 3Ch for high-resolution mode)
CH=8251A mode word (asynchronous mode)
bit 7,6: stop bit length
11b = 2 bits
10b = 1.5 bits
01b = 1 bit
bit 5: Parity specification
1 = Even parity
0 = Odd parity
bit 4: Parity presence/absence
1 = Yes
0 = No
bit 3,2: character length
11b = 8 bits
10b = 7 bits
01b = 6 bits
00b = 5 bits
bit 1,0: clock rate
11b = 64 times
10b = 16 times
CL=8251A command word
bit 6: internal reset
1 = yes
0 = no
bit 5: RTS terminal
1 = ON
0 = OFF
bit 4: error flag reset
1 = Yes
0 = No
bit 3: Send break signal
1 = Yes
0 = No
bit 2: Receive enabled
1 = Enabled
0 = Disabled
bit 1: DTR terminal
1 = ON
0 = OFF
bit 0: Send enabled
1 = Enabled
0 = Disabled
ES:DI=Start address of buffer control block
DX=Receive buffer size (unit: byte)
Output AH=Return code
00h=Normal end
04h=When channel 1 or 2 is specified, the extended RS-232C interface board is not connected■[Hi-Res]
AL=Undefined
Explanation o Initialize the RS-232C BIOS in asynchronous mode. XON/XOFF flow control is not performed during reception and transmission.
o Synchronous communication is not supported by the RS-232C BIOS.
o The receive buffer is allocated immediately after the buffer control block specified by ES:DI.
The top address of the receive buffer is ES:DI+14h in normal mode and PC-98LT/HA, and ES:DI+18h in high-resolution mode.
The end of the receive buffer is ES:DI+14h+DX-1 for all models. In high-resolution mode, the size of the buffer control
block is 4 bytes larger than in normal mode, but the actual receive buffer size is reduced by 4 bytes from the value
specified by DX to ensure compatibility.
o The number of receive characters that can be stored in the receive buffer is half the actual receive buffer size.
In single mode, the receive buffer stores the received character (1 byte) and the 8251A status (1 byte) at the time the character was received.
u In normal mode, the MS-DOS AUX driver traps this function. Note that the function's functionality and register interface are incompatible with the BIOS. See INT 19h - Function 00h (RSDRV).
o In high-resolution mode, the transfer speeds for channels 1 and 2 are set with the DIP switches on the extended RS-232C interface board.
o In normal mode, a different interrupt is assigned to each channel.
Channel 0 = INT 19h, channel 1 = INT D4h, channel 2 = INT D5h. The register interface for INT D4h and D5h is the same as for INT 19h.
u To determine whether the device supports 19200bps, refer to F8E8:0002h (normal) or FFE8:0002h (high-resolution).
If the device supports 19200bps, 19200bps can be used in the BIOS even in high-resolution mode on the 98 High Resolution Board (PC-9821A-E02).
o For details on the buffer control block, etc., refer to the Technical Data Book.
Related INT 19h - Function 01h
INT 19h - Function 07h [Hi-Res]
0000:0556h
0000:055Bh
0000:05C1h
0000:05F0h
0000:05F4h
F8E8:0002h bit 2 [Normal]
FFE8:0002h bit 2 [Hi-Res]
I/O 0030h
I/O 0035h
I/O 0075h
I/O 00B0h
INT 19h - Function 01h (BIOS)
Classification RS-232C BIOS
Name Initialization with flow control (single mode)
Target Normal, High Resolution, PC-98LT/HA
Input AH=01h: Channel 0 (built-in RS-232C)
11h: Channel 1 (Extended RS-232C interface) ■ [High Resolution]
21h: Channel 2 (Extended RS-232C interface) ■ [High Resolution]
AL=Transfer speed ■ [Only channel 0 is valid]
* Same as INT 19h - Function 00h (BIOS)
BH=Timeout time when sending (unit: 500 ms)
* Same as INT 19h - Function 00h (BIOS)
BL=Timeout time when receiving (unit: 500 ms)
* Same as INT 19h - Function 00h (BIOS)
CH=8251A mode word (asynchronous mode)
* INT 19h - Same as Function 00h (BIOS)
CL=Command word for 8251A
* Same as INT 19h - Function 00h (BIOS)
ES:DI=Start address of buffer control block
DX=Receive buffer size (unit: byte)
Output AH=Return code
00h=Normal end
04h=When channel 1 or 2 is specified, the extended RS-232C interface board is not connected■[Hi-Res]
AL=Undefined
Explanation o Initializes the RS-232C BIOS in asynchronous mode. Performs XON/XOFF flow control when receiving.
Does not perform XON/XOFF flow control when sending. The RS-232C BIOS in normal mode does not support XON/XOFF flow control when sending.
Otherwise, it is the same as INT 19h - Function 00h (BIOS).
u In normal mode, the MS-DOS AUX driver traps this function. In this case, please note that the function and register interface are not
compatible with the BIOS. See INT 19h - Function 01h (RSDRV).
o In normal mode, a different interrupt is assigned to each channel.
Channel 0 = INT 19h, Channel 1 = INT D4h, Channel 2 = INT D5h. The register interface for INT D4h and D5h is the same as INT 19h.
Related INT 19h - Function 00h
INT 19h - Function 07h [Hi-Res]
I/O 0030h
I/O 0035h
I/O 0075h
I/O 00B0h
INT 19h - Function 02h (BIOS)
Classification RS-232C BIOS
Name Get received data length
Target Normal, High Resolution, PC-98LT/HA
Input AH=02h: Channel 0 (built-in RS-232C)
12h: Channel 1 (Extended RS-232C interface) ■ [High Resolution]
22h: Channel 2 (Extended RS-232C interface) ■ [High Resolution]
Output AH=Return code
00h=Normal termination
01h=RS-232C BIOS not initialized
02h=Receive buffer overflow
CX=Number of received characters in receive buffer
Explanation o Check the number of received characters stored in the receive buffer.
In single mode, and when the receive buffer is managed in word units in extended mode, the received characters and
status are stored in the receive buffer as a set of 2 bytes, but even in this case, the value
returned by this function is the number of received characters.
u Once a receive buffer overflow (AH=02h) notification is received by the return code, the flag indicating the overflow is cleared in the BIOS.
o When the receive buffer overflows in extended mode, the 8251A must be initialized.
u In normal mode, the MS-DOS AUX driver traps this function. Note that the function's functionality and register
interface are incompatible with the BIOS. See INT 19h - Function 02h (RSDRV).
o In normal mode, a different interrupt is assigned to each channel.
Channel 0 = INT 19h, channel 1 = INT D4h, channel 2 = INT D5h. The register interface for INT D4h and D5h is the same as for INT 19h.
Related
INT 19h - Function 03h (BIOS)
Classification RS-232C BIOS
Name Data transmission
Target Normal, Hi-Res, PC-98LT/HA
Input AH=03h: Channel 0 (built-in RS-232C)
13h: Channel 1 (Extended RS-232C interface) ■ [Hi-Res]
23h: Channel 2 (Extended RS-232C interface) ■ [Hi-Res]
AL=Transmit data
CL=Reference status bit ■ [Extended mode]
bit 7=DSR terminal
bit 6=CTS terminal
bit 5-3=000b
bit 2=TxEMPTY flag
bit 1,0=00b
Output AH=Return code
00h=Normal termination
01h=RS-232C BIOS not initialized
02h=Receive buffer overflow
03h=Timeout
05h=When XON/XOFF is enabled during transmission, transmission is stopped by receiving XOFF ■ [Hi-Res]
AH = Undefined
Explanation o Transmits 1 byte of data.
No buffering of transmitted data is performed.
u Once a notification of receive buffer overflow (AH=02h) is received in the return code, the flag indicating overflow in the BIOS is cleared.
o When the receive buffer overflows in extended mode, the 8251A must be initialized.
u In normal mode, the MS-DOS AUX driver traps this function. Note that the function and register
interface are incompatible with the BIOS. See INT 19h - Function 03h (RSDRV).
o In normal mode, a different interrupt is assigned to each channel.
Channel 0 = INT 19h, Channel 1 = INT D4h, Channel 2 = INT D5h. The register interface for INT D4h and D5h is the same as INT 19h.
o For details on the buffer control block, etc., see the Technical Data Book.
Related
INT 19h - Function 04h (BIOS)
Classification RS-232C BIOS
Name Receiving data
Target Normal, Hi-Res, PC-98LT/HA
Input AH=04h: Specify channel 0 (built-in RS-232C)
14h: Specify channel 1 (Extended RS-232C interface) ■ [Hi-Res]
24h: Specify channel 2 (Extended RS-232C interface) ■ [Hi-Res]
Output AH=Return code
00h=Normal termination
01h=RS-232C BIOS not initialized
02h=Receive buffer overflow
03h=Timeout
CH=Received data
CL=Status when receiving data
bit 7:DSR
1=ON
0=OFF
bit 6:BREAK
1=Detected
0=Not detected
bit 5:Framing error
1=Detected
0=Not detected
bit 4:Overrun error
1=Detected
0=Not detected
bit 3: Parity error
1=Detected
0=Not detected
bit 2:■[Normal]TxEMPTY
1=Transmit buffer empty
0=Transmit buffer full
bit 2:■[Hi-Res]System port status CI#
1=OFF
0=ON
bit 1:System port status CTS#
1=OFF
0=ON
bit 0:System port status CD#
1=OFF
0=ON
Explanation o Extracts one byte of received data from the receive buffer and outputs the received data and status.
If there is no received data in the receive buffer, waits for the receive timeout period set at initialization.
o When the receive buffer is managed in byte units in extended mode, returns the current status to CL.
u Once a receive buffer overflow (AH=02h) notification is received in the return code, the flag indicating overflow in the BIOS is cleared.
o In extended mode, if the receive buffer overflows, the 8251A must be initialized.
u In normal mode, the MS-DOS AUX driver traps this function. Note that in this case, the function's functionality and
register interface are incompatible with the BIOS. See INT 19h - Function 04h (RSDRV).
o In normal mode, a different interrupt is assigned to each channel.
Channel 0 = INT 19h, channel 1 = INT D4h, channel 2 = INT D5h. The register interface for INT D4h and D5h is the same as for INT 19h.
o For details on the buffer control block, etc., see the Technical Data Book.
Related
INT 19h - Function 05h (BIOS)
Classification RS-232C BIOS
Name Command output to 8251A
Target Normal, Hi-Res, PC-98LT/HA
Input AH=05h: Specify channel 0 (built-in RS-232C)
15h: Specify channel 1 (expanded RS-232C interface) ■ [Hi-Res]
25h: Specify channel 2 (expanded RS-232C interface) ■ [Hi-Res]
AL=Command to output to 8251A
* Same as INT 19h - Function 00h (BIOS)
Output AH=Return code
00h=Normal termination
01h=RS-232C BIOS not initialized
02h=Receive buffer overflow
Explanation o Write a command word to 8251A.
u The technical data book states that the "command to be output to the 8251A" should be specified in CL, but in reality it is specified in AL.
u Once a notification of receive buffer overflow (AH=02h) is received in the return code, the flag indicating overflow is cleared in the BIOS.
o When the receive buffer overflows in extended mode, the 8251A must be initialized.
u In normal mode, the MS-DOS AUX driver traps this function. Note that the function's functionality and
register interface are incompatible with the BIOS. See INT 19h - Function 05h (RSDRV).
u The PC-98HA technical data book states that the return code is returned in AL, but in reality it is returned in AH.
o In normal mode, a different interrupt is assigned to each channel.
Channel 0=INT 19h, channel 1=INT D4h, channel 2=INT D5h. The register interface for INT D4h and D5h is the same as that for INT 19h.
For details on the buffer control block, etc., see the Technical Data Book.
Related
INT 19h - Function 06h (BIOS)
Classification RS-232C BIOS
Name Get status
Target Normal, Hi-Res, PC-98LT/HA
Input AH=06h: Specify channel 0 (built-in RS-232C)
16h: Specify channel 1 (Extended RS-232C interface) ■ [Hi-Res]
26h: Specify channel 2 (Extended RS-232C interface) ■ [Hi-Res]
Output AH=Return code
00h=Normal termination
01h=RS-232C not initialized
02h=Receive buffer overflow
CH=8251A status
bit 7:DSR
1=ON
0=OFF
bit 6:BREAK
1=Detected
0=Not detected
bit 5:Framing error
1=Detected
0=Not detected
bit 4:Overrun error
1=Detected
0=Not detected
bit 3: Parity error
1=Detected
0=Not detected
bit 2:TxEMPTY
1=Transmit buffer empty
0=Transmit buffer full
bit 1:RxREADY
1=Received character
0=No received character
bit 0:TxREADY
1=Transmit ready
0=Transmit busy
CL=Modem status
bit 7:CI#
1=OFF
0=ON
* The original PC-9801 does not support CI#. Always 0.
bit 6:CTS#
1=OFF
0=ON
bit 5:CD#
1=OFF
0=ON
bit 4-0:Reserved
Explanation o Gets the current status of RS-232C.
u Once a notification of receive buffer overflow (AH=02h) is received in the return code, the flag indicating overflow in the BIOS is cleared.
o In extended mode, if the receive buffer overflows, the 8251A must be initialized.
u In normal mode, the MS-DOS AUX driver traps this function. Note that the functionality and register interface of the
function are incompatible with the BIOS. See INT 19h - Function 06h (RSDRV).
o In normal mode, a different interrupt is assigned to each channel.
Channel 0=INT 19h, channel 1=INT D4h, channel 2=INT D5h. The register interface for INT D4h and INT D5h is the same as that for INT 19h.
o For details on the buffer control block, etc., see the Technical Data Book.
Related I/O 0033h
INT 19h - Function 07h (BIOS)
Classification RS-232C BIOS
Name Initialize RS-232C BIOS (Extended Mode)
Target Hi-Res
Input AH=07h: Specify channel 0 (built-in RS-232C)
17h: Specify channel 1 (Extended RS-232C interface)
27h: Specify channel 2 (Extended RS-232C interface)
AL=Transfer speed■[Only channel 0 is valid]
* Same as INT 19h - Function 00h (BIOS)
BX=BIOS control information
bit 15:Reserved
bit 14:SI/SO control
1=Perform
0=Do not perform
bit 13:Sender X flow control
1=Yes
0=No
bit 12:Receiver X flow control
1=Yes
0=No
bit 11:ER (DTR) signal control when receive buffer full
1=Yes (ER OFF)
0=No
bit 10: RS (RTS) signal control when receive buffer is full
1=Yes (RS OFF)
0=No
bit 9,8: Processing of received DEL (7Fh/FFh)
11b=Ignore
10b=Convert to BS (08h)
01b=Convert to NULL (00h)
00b=No conversion
bit 7-1: Reserved
bit 0: Receive buffer management
1=Word unit
0=Byte unit
CH=8251A mode word (asynchronous mode)
* Same as INT 19h - Function 00h (BIOS)
CL=8251A command word
* Same as INT 19h - Function 00h (BIOS)
DX=Receive buffer size
ES:DI=First address of buffer control block
Output AH=Return code
00h=Normal end
04h=Channel 1, 2 specified, no expansion RS-232C interface board is connected
Explanation o Initialize the RS-232C BIOS in asynchronous mode.
You can also select XON/XOFF flow control during reception and transmission.
When initialized with this function, INT 1Fh - Function 83h is executed at the end of each reception interrupt (after EOI is issued).
o The receive buffer is allocated immediately after the buffer control block specified by ES:DI.
The start address of the receive buffer is ES:DI+18h, and the end address is ES:DI+18h+DX-1.
o When the receive buffer is managed in word units (BX bit 0=1), the number of receive characters that can be stored in the
receive buffer is half the actual receive buffer size. This is because the receive buffer stores the received character (1 byte) and
the 8251A status (1 byte) at the time the character was received.
When the receive buffer is managed in bytes (BX bit 0=0), the number of received characters can be stored equal to the actual receive buffer size.
o Other than that, it is the same as INT 19h - Function 00h (BIOS).
o For details on the buffer control block, etc., see the Technical Data Book.
Related INT 19h - Function 00h (BIOS)
INT 1Fh - Function 83h [Hi-Res]
I/O 0030h
I/O 0035h
I/O 0075h
I/O 00B0h