Specifications

Software Configuration
3–19
AND AL,1 ;see if data received
JZ In2
POP DX
POP AX
IRET
;
; *********INTERRUPT INITIALIZATION ROUTINE*********
;
MOV DX,OFFSET SerInt
MOV AL,0Ch ;set the vector for IRQ4
PUSH DS
PUSH CS
POP DS
; set the vector for INT13 using a DOS function call
MOV AH,25h ;set the interrupt vector in AL
INT 21h ;the vector is in DS:DX
;
POP DS ;restoreDS
IN AL,INTR1
AND AL,0EFh ;unmask IRQ4
OUT INTR1,AL
MOV AL,64h ;clear interrupt 4 flag
OUT INTR,AL
;
; ****************PORT ADDRESS TABLE****************
;
Ser3 DW 3E8h ;base address of Serial 3
Ser1 DW 3F8h ;base address of Serial 1
;
Ifl3 DW 3eah ;status register of Serial 3
Ifl1 DW 3fah ;status register of Serial 1
;
3.9.3 Serial Console Features
To use the serial console features, connect the serial console device(s) to Serial 1 or Serial 2. Use SETUP
to configure the Little Board/486i to use its serial console support feature. The configuration memory
stores serial console support parameters.
Caution
Be careful when changing the console configuration using SETUP.
If you specify “None” for console input and output, there will be no
console access to the system. (You can recover from this state by
removing the serial console plug from the primary serial port
connector and shorting pins 7/8.)
SETUP provides separate configurations for serial console input and output. Thus, you can use a serial
port (and attached serial device) for either or both input and output. For instance, you can use a modem or