Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
TC: int bioscom( int cmd, char byte, int port )
- prototype in bios.h
- RS232 communications
- cmd = 0 to set comm parms to value in byte
1 to send char in byte out on RS232 line
2 to receive char
3 to return current port status
- port = 0 for COM1
1 for COM2
2 for COM3
3 for COM4
- byte = bitwise OR of following bits
0x02 = 7 data bits 0x00 = 1 stop bit
0x03 = 8 data bits 0x04 = 2 stop bits
0x00 == no parity;
0x08 == odd parity;
0x18 == even parity
0x00 110 bps 0x20 150 bps
0x40 300 bps 0x60 600 bps
0x80 1200 bps 0xa0 2400 bps
0xc0 4800 bps 0xe0 9600 bps
- returns 16-bit integer, upper 8 bits are status & lower 8 bits
depending on cmd sent
│7│6│5│4│3│2│1│0│ low byte (AL) modem status
│ │ │ │ │ │ │ └──── delta clear to send
│ │ │ │ │ │ └───── delta data set ready
│ │ │ │ │ └────── trailing edge ring detector
│ │ │ │ └─────── delta receive line signal detect
│ │ │ └──────── clear to send
│ │ └───────── data set ready
│ └────────── ring indicator
└─────────── receive line signal detect
│F│E│D│C│B│A│9│8│ high byte (AH) line status
│ │ │ │ │ │ │ └──── data ready
│ │ │ │ │ │ └───── overrun error
│ │ │ │ │ └────── parity error
│ │ │ │ └─────── framing error
│ │ │ └──────── break detect
│ │ └───────── transmit holding register empty
│ └────────── transmit shift register empty
└─────────── time out
- MS C uses _bios_serialcomm()
- see INT 14
[helppc.bosbyte.nl] bioscom