Chapter 3: Software Installation - DOS
3-5
Echo
User's Manual, ver. 0.00
Function 0 - Initialize the port
Input: ah
=
0
al = baud, parity, length
dx = channel ( 0 = com1, 1 = com2, ... )
Bit designations for al are:
7
data length
1 0 - 7 bits
1 1 - 8 bits
stop bits
0 - 1 bit
1 - 2 bits
parity
0 0 - none
0 1 - odd
1 1 - even
baud rate
0 0 0 - 110 bps
0 0 1 - 150 bps
0 1 0 - 300 bps
0 1 1 - 600 bps
1 0 0 - 1200 bps
1 0 1 - 2400 bps
1 1 0 - 4800 bps
1 1 1 - 9600 bps
6
5
4
3
2
1
0
Return: ax as per
Function 3
Function 1 - Output a character
Input: ah
=
1
al = character
dx = port number
Return: timeout if bit 7 of ah is set