Table 6-Ia. - PGSC 486 Serial Communication Ports Configuration 1 (Undocked)
COM Port Description
COM Number
IRQ Number
I/O Address Location
DMA

Channel
Controller
Internal

RS-232D
COM1
IRQ4
03F8-03FF
N/A
16550 UART

Equivalent
PC-Card

Ethernet
N/A
IRQ7**
0140-015F
N/A
Internal

to PC-Card

**An interrupt conflict may occur between the Ethernet and the parallel port if used at the same time. Simultaneous interrupt use should be avoided. The parallel port does not use interrupts during normal printing. The Ethernet remains on IRQ7 in this configuration for commonality with the other configurations.

Table 6-IIa. - PGSC 486 Interrupt Settings Configuration 1 (Undocked)
Interrupt Num
Device
I/O Address
DMA Channel
IRQ0Timer 0040-0043N/A
IRQ1Keyboard 0060,0064N/A
IRQ2Cascade Int. N/AN/A
IRQ3Unused TBDN/A
IRQ4RS-232 on Back 03F8-03FFN/A
IRQ5Unused TBDN/A
IRQ6Floppy Disk 03F0-03F72
IRQ7Ethernet PCMCIA & Parallel Port 0140-015F

03BC-03BE

N/A
IRQ8Real Time Clock 0070-0071N/A
IRQ9Video Control Video Addr*N/A
IRQ10Audio Card 4E30-4E3F0 AND 1
IRQ11Unused TBDN/A
IRQ12Trackpoint II (mouse) 0060,0064N/A
IRQ13486 Floating Point Unit Exc (Math CoProc) N/AN/A
IRQ14Hard Disk Drive 01F0-01F7

03F6-03F7

N/A
IRQ15Unused N/AN/A

Note: Chart is only valid for the ThinkPad 755C with no expansion unit.

*Video Addr = 03B4-03B5, 03BA, 03C0-03C9, 03CA, 03CC, 03CE-03CF, 03D4-03D5, 03DA,

& 23C0-23C7

With Windows 95, the PCMCIA controller is polling-driven and does not use interrupt 15.

Table 6-Ib. - PGSC Serial Communication Ports Configuration 2 (RS-422 & PCMMU)
COM Port Description
COM Number
IRQ Number
I/O

Address Location
DMA

Channel
Controller
Internal

RS-232D
COM1
IRQ4
03F8-03FF
N/A
16550

UART

Equivalent
Exp. Unit

RS-422 #1

(Card #1)
COM2
IRQ3
02F8-02FF
N/A
PC-16550

UART
Exp. Unit

RS-422 #2

(Card #1)
COM3
IRQ5
03E8-03EF
N/A
PC-16550

UART
Exp. Unit

PCMMU

(Card #2)
SCC1A and

SCC1B
IRQ9*
0238-023F
1 and 3
Zilog

8530
PC-Card

Ethernet
N/A
IRQ7**
0140-015F
N/A
Internal to

PC-Card

*IRQ2 is also required to use IRQ9. IRQ2 is used as the cascade interrupt for controlling IRQ8

through IRQ15.

*IRQ9 is also used for the ThinkPad 755C's video controller.

**An interrupt conflict may occur between the Ethernet and the parallel port if used at the same time.

Simultaneous interrupt use should be avoided. The parallel port does not use interrupts during normal

printing.

Table 6-IIb. - PGSC 486 Interrupt Settings Configuration 2 (RS-422 & PCMMU)
Interrupt Num
Device
I/O Address
DMA Channel
IRQ0Timer 0040-0043N/A
IRQ1Keyboard 0060,0064N/A
IRQ2Cascade Int. N/AN/A
IRQ3RS-422 #1 02F8-02FFN/A
IRQ4RS-232 on Back 03F8-03FFN/A
IRQ5RS-422 #2 03E8-03EFN/A
IRQ6Floppy Disk 03F0-03F72
IRQ7Ethernet PCMCIA &

Parallel Port

0140-015F

03BC-03BE

N/A
IRQ8Real Time Clock 0070-0071N/A
IRQ9PCCMMU Card & Video Control 0238-023F

Video Addr*

1 AND 3
IRQ10Audio Card 4E30-4E3F0 AND 1
IRQ11Reserved for SCSI Card CA000-CBFFF

(Memory Loc)

N/A
IRQ12Trackpoint II (mouse) 0060,0064N/A
IRQ13486 Floating Point Unit Exc (Math CoProc) N/AN/A
IRQ14Hard Disk Drive 01F0-01F7

03F6-03F7

N/A
IRQ15Unused N/AN/A

Chart is only valid for the ThinkPad 755C with Configuration 2 expansion unit.

*Video Addr = 03B4-03B5, 03BA, 03C0-03C9, 03CA, 03CC, 03CE-03CF, 03D4-03D5, 03DA,

& 23C0-23C7

With Windows 95, the PCMCIA controller is polling-driven and does not use interrupt 15.

Table 6-Ic. - PGSC 486 Serial Communication Ports Configuration 3 (OCA & RS-422)
COM Port Description
COM Number
IRQ Number
I/O Address Location
DMA

Channel
Controller
Internal

RS-232D
COM1
IRQ4
03F8-03FF
N/A
16550 UART

Equivalent
Exp. Unit*

RS-422 #2

(Card #1)
COM3
IRQ5
03E8-03EF
N/A
PC-16550

UART
OCA/PADM

(Card #2)
COM2
IRQ3
02F8-02FF

0200-0221
N/A
Unique
OCA/Ku-Band

(Card #2)
N/A
IRQ11
02E8-02EF

02E0-02E7
N/A
Unique
PC-Card

Ethernet
N/A
IRQ7**
0140-015F
N/A
Internal to

PC-Card

*Only one of the two RS-422 ports available on the board will be enabled in this configuration.

Placing a cap on the first port is recommended.

**An interrupt conflict may occur between the Ethernet and the parallel port if used at the same time.

Simultaneous interrupt use should be avoided. The parallel port does not use interrupts during normal

printing.

Table 6-IIc. - PGSC 486 Interrupt Settings Configuration 3 (OCA & RS-422)
Interrupt Num
Device
I/O Address
DMA Channel
IRQ0Timer 0040-0043N/A
IRQ1Keyboard 0060,0064N/A
IRQ2Cascade Int. N/AN/A
IRQ3OCA/PADM 02F8-02FF

0200-0221

N/A
IRQ4RS-232 on Back 03F8-03FFN/A
IRQ5RS-422 #2 03E8-03EFN/A
IRQ6Floppy Disk 03F0-03F72
IRQ7PCMCIA Ethernet & Parallel Port 0140-015F

03BC-03BE

N/A
IRQ8Real Time Clock 0070-0071N/A
IRQ9Video Control Video Addr*N/A
IRQ10Audio Card 4E30-4E3F0 and 1
IRQ11OCA/Ku-Band 02E8-02EF

02E0-02E7

N/A
IRQ12Trackpoint II (mouse) 0060,0064N/A
IRQ13486 Floating Point Unit Exc (Math CoProc) N/AN/A
IRQ14Hard Disk Drive 01F0-01F7

03F6-03F7

N/A
IRQ15Unused N/AN/A

Chart is only valid for the ThinkPad 755C with Configuration 3 expansion unit.

*Video Addr = 03B4-03B5, 03BA, 03C0-03C9, 03CA, 03CC, 03CE-03CF, 03D4-03D5, 03DA,

& 23C0-23C7

With Windows 95, the PCMCIA controller is polling-driven and does not use interrupt 15.

Table 6-Id. - PGSC 486 Serial Communication Ports Configuration 4 (OCA & PCMMU)
COM Port Description
COM Number
IRQ Number
I/O

Address Location
DMA

Channel
Controller
Internal

RS-232D
COM1
IRQ4
03F8-03FF
N/A
16550

UART

Equivalent
PCMMU

(Card #1)
SCC1A and

SCC1B
IRQ9*
0238-023F
1 and 3
Zilog

8530
OCA/PADM

(Card #2)
COM2
IRQ3
02F8-02FF

0200-0221
N/A
Unique
OCA/Ku-Band

(KCA)

(Card #2)
N/A
IRQ11
02E8-02EF

02E0-02E7
N/A
Unique
PC-Card

Ethernet
N/A
IRQ7**
0140-015F
N/A
Internal to

PC-Card

*IRQ2 is also required to use IRQ9. IRQ2 is used as the cascade interrupt for controlling IRQ8

through IRQ15.

*IRQ9 is also used for the ThinkPad 755C's video controller.

**An interrupt conflict may occur between the Ethernet and the parallel port if used at the same time.

Simultaneous interrupt use should be avoided. The parallel port does not use interrupts during normal

printing.

Table 6-IId. - PGSC 486 Interrupt Settings Configuration 4 (OCA & PCMMU)
Interrupt NumDevice I/O AddressDMA Channel
IRQ0Timer 0040-0043N/A
IRQ1Keyboard 0060,0064N/A
IRQ2Cascade Int. N/AN/A
IRQ3OCA/PADM 02F8-02FF

0200-0221

N/A
IRQ4RS-232 on Back 03F8-03FFN/A
IRQ5Unused N/A
IRQ6Floppy Disk 03F0-03F72
IRQ7PCMCIA Ethernet & Parallel Port 0140-015F

03BC-03BE

N/A
IRQ8Real Time Clock 0070-0071N/A
IRQ9PCMMU and

Video Control

0238-023F

Video Addr*

1 and 3
IRQ10Audio Card 4E30-4E3F0 and 1
IRQ11OCA/Ku-Band 02E8-02EF

02E0-02E7

N/A
IRQ12Trackpoint II (mouse) 0060,0064N/A
IRQ13486 Floating Point Unit Exc (Math CoProc) N/AN/A
IRQ14Hard Disk Drive 01F0-01F7

03F6-03F7

N/A
IRQ15Unused N/AN/A

Chart is only valid for the ThinkPad 755C with Configuration 4 expansion unit.

*Video Addr = 03B4-03B5, 03BA, 03C0-03C9, 03CA, 03CC, 03CE-03CF, 03D4-03D5, 03DA,

& 23C0-23C7

With Windows 95, the PCMCIA controller is polling-driven and does not use interrupt 15.

Table 6-Ie. - PGSC 486 Serial Communication Ports Configuration 5 (OCA & ProShare)
COM Port Description
COM Number
IRQ Number
I/O Address Location
DMA

Channel
Controller
Internal

RS-232D
COM1
IRQ4
03F8-03FF
N/A
16550 UART

Equivalent
ProShare

(Card #1)
N/A
IRQ15
0224-0227

0240-0240F
N/A
Unique
OCA/PADM

(Card #2)
COM2
IRQ3
02F8-02FF

0200-0221
N/A
Unique
OCA/Ku-Band

(Card #2)
N/A
IRQ11
02E8-02EF

02E0-02E7
N/A
Unique
PC-Card

Ethernet
N/A
IRQ7**
0140-015F
N/A
Internal to

PC-Card

**An interrupt conflict may occur between the Ethernet and the parallel port if used at the same time.

Simultaneous interrupt use should be avoided. The parallel port does not use interrupts during normal

printing.

Table 6-IIe. - PGSC Interrupt Settings Configuration 5 (OCA & ProShare)
Interrupt NumDevice I/O AddressDMA Channel
IRQ0Timer 0040-0043N/A
IRQ1Keyboard 0060,0064N/A
IRQ2Cascade Int. N/AN/A
IRQ3OCA/PADM 02F8-02FF

0200-0221

N/A
IRQ4RS-232 on Back 03F8-03FFN/A
IRQ5Unused N/AN/A
IRQ6Floppy Disk 03F0-03F72
IRQ7PCMCIA Ethernet & Parallel Port 0140-015F

03BC-03BE

N/A
IRQ8Real Time Clock 0070-0071N/A
IRQ9Video Control 0238-023F, Video Addr* 1 and 3
IRQ10Audio Card 4E30-4E3F0 and 1
IRQ11OCA/Ku-Band 02E8-02EF

02E0-02E7

N/A
IRQ12Trackpoint II (mouse) 0060,0064N/A
IRQ13486 Floating Point Unit Exc (Math CoProc) N/AN/A
IRQ14Hard Disk Drive 01F0-01F7

03F6-03F7

N/A
IRQ15ProShare 0224-0227

0240-024F

N/A

Chart is only valid for the ThinkPad 755C with Configuration 5 expansion unit.

*Video Addr = 03B4-03B5, 03BA, 03C0-03C9, 03CA, 03CC, 03CE-03CF, 03D4-03D5, 03DA,

& 23C0-23C7

With Windows 95, the PCMCIA controller is polling-driven and does not use interrupt 15.