WonderWitch/FreyaBIOS/Communication

The Communication (comm) interrupt provides an abstraction layer and helpers for the WonderSwan's serial port.

Interrupts

INT $14/AH=$00 - comm_open

• AH = $00

Opens the serial port. Note that the baud rate must be set before calling comm_open.

INT $14/AH=$01 - comm_close

• AH = $01

Closes the serial port.

INT $14/AH=$02 - comm_send_char

• AH = $02
• BL = Character (byte) to send.

Return:

• AX = Return code.

Return codes:

• 0x0000 - Success
• 0x8101 - Transfer timeout
• 0x8102 - Transfer RX overrun
• 0x8103 - Transfer cancelled

INT $14/AH=$03 - comm_receive_char

• AH = $03

Return:

• AX = Character (byte) read (0x0000 - 0xFFFF) or error return code.

INT $14/AH=$04 - comm_receive_with_timeout

• AH = $03
• CX = Timeout, in frames (as in comm_set_timeout).

Return:

• AX = Character (byte) read (0x0000 - 0xFFFF) or error return code.

Unlike comm_receive_char, this function uses an user-provided timeout.

INT $14/AH=$05 - comm_send_string

• AH = $05
• DS:DX = Input string to send.

Return:

• AX = Return code.

INT $14/AH=$06 - comm_send_block

• AH = $06
• CX = Buffer size, in bytes.
• DS:DX = Input buffer to send.

Return:

• AX = Return code.

INT $14/AH=$07 - comm_receive_block

• AH = $07
• CX = Buffer size, in bytes.
• DS:DX = Buffer to receive bytes to.

Return:

• AX = Return code.
• DX = Number of bytes successfully received.

INT $14/AH=$08 - comm_set_timeout

• AH = $08
• BX = Receive timeout (in frames; 0xFFFF - wait forever)
• CX = Send timeout (in frames; 0xFFFF - wait forever)

INT $14/AH=$09 - comm_set_baudrate

• AH = $09
• BX = Baud rate (0 = 9600 bps, 1 = 38400 bps).

Only affects newly opened serial port connections.

INT $14/AH=$0A - comm_get_baudrate

• AH = $0A

Return:

• AX = Baud rate (0 = 9600 bps, 1 = 38400 bps).

INT $14/AH=$0B - comm_set_cancel_key

• AH = $0B
• BX = Cancel key combination.

INT $14/AH=$0C - comm_get_cancel_key

• AH = $0C

Return:

• AX = Cancel key combination.

INT $14/AH=$0D - comm_xmodem

TODO