Serial Ports Com1-Com2; Floppy Disk Interface; Controllers; Interrupt Controllers - DIGITAL-LOGIC Microspace MSB900L User Manual

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5.4.3.

Serial Ports COM1-COM2

The serial channels are fully compatible with 16C550 UARTS. COM1 is the primary serial port, and is sup-
ported by the board's ROM-BIOS as the PC-DOS 'COM1' device. The secondary serial port is COM2; it is
supported as the 'COM2' device.
Standard: COM 1/2: National PC87317VUL: 2 x 16C550 compatible serial interfaces
Serial Port Connectors COM1, COM2
Pin Signal Name
1 CD
2 DSR
3 RXD
4 RTS
5 TXD
6 CTS
7 DTR
8 RI
9 GND
The serial port signals are compatible with the RS232C specifications.
5.4.4.

Floppy Disk Interface

This is not available with this product; use a USB Floppy.

5.5. Controllers

5.5.1.

Interrupt Controllers

An 8259A compatible interrupt controller, within the chipset, provides seven prioritized interrupt levels. Of
these, several are normally associated with the board's onboard device interfaces and controllers, and sev-
eral are available on the AT expansion bus.
Interrupt: Sources:
IRQ0 ROM-BIOS clock tick function, from timer 0
IRQ1 Keyboard controller output buffer full
IRQ2 Used for cascade 2. 8259
IRQ3 COM2 serial port
IRQ4 COM1 serial port
IRQ5 LPT2 parallel printer (if present)
IRQ6 Floppy controller
IRQ7 LPT1 parallel printer
IRQ8 Battery backed clock
IRQ9 Free for user
IRQ10 Free for user
IRQ11 Free for user
IRQ12 PS/2 mouse
IRQ13 Math. coprocessor
IRQ14 Hard disk IDE
IRQ15 Free for user
Function
Data Carrier Detect
Data Set Ready
Receive Data
Request To Send
Transmit Data
Clear to Send
Data Terminal Ready
Ring Indicator
Signal Ground
27
MSB900/L Detailed Technical Manual V1.0
in/out DB25 Pin DB9 Pin
in 8
in 6
in 3
out 4
out 2
in 5
out 20
in 22
7
Onboard used:
yes
yes
yes
yes
yes
no *
yes
yes
yes
no *
no *
no *
yes
yes
yes
no *
* It may depend on the LAN configuration.
1
6
2
7
3
8
4
9
5