Compaq Deskpro EN Specfications page 2

System Board Connectors and Jumpers (position of some untitled components may vary in location)
CR508 3.3V Aux LED
CR570 5V Aux (ON)/PS_ON_(OFF) LED
E49 Password jumper (Installed = Enabled,
Removed = Cleared)
J30 Riser board
P1 Power supply connector
P6 Speaker connector
P7 CD-ROM audio
P10 Diskette drive connector
Riser Board Connectors and Jumpers
J20 PCI slot
J21 PCI slot
J22 PCI slot
P7 CD audio connector
System Hardware Interrupts
IRQ System Function
0 Timer Interrupt
1 Keyboard
2 Interrupt Controller Cascade
3 Serial Port (COM B)
4 Serial Port (COM A)
5 Unused, available for PCI
6 Diskette Drive
7 Parallel Port (LPT 1)
System Hardware DMA
DMA System Function
0 Unused
1 Unused
2 Diskette Drive
3 ECP Parallel Port LPT1
(Default; Alternate = DMA 0)
ICH Fixed I/O Registers
Port Register Name
00h, 02h, 04h, 06h Channel 0, 1, 2, 3 DMA base and current address register
C0h, C4h, C8h, CCh Channel 4, 5, 6, 7 DMA base and current address register
01h, 03h, 05h, 07h Channel 0, 1, 2, 3 DMA base and current count register
C2h, C6h, Cah, CEh Channel 4, 5, 6, 7 DMA base and current count register
10h-1Fh Aliased at 00h-0Fh
20h Master PIC ICW1 Init. Cmd Word 1 register, Master PIC OCW2 Init. Cmd Word 2
register, and Master PIC OCW3 Init. Cmd Word 3 register
21h Master PIC OCW1 Init. Cmd Word 1 register, Master PIC ICW2 Init. Cmd Word 2
register, and Master PIC ICW3 Init. Cmd Word 3 register
24h,-25h, 28-29h, 2Ch-2Dh, 30h- Aliased at 20h-21h
31h, 34h-35h, 38h-39h, 3Ch-3Dh
40h Counter 0 interval time status byte format and Counter 0 counter access port regis-
ter
41h Counter 1 interval time status byte format and Counter 1 counter access port regis-
ter
42h Counter 2 interval time status byte format and Counter 2 counter access port regis-
ter
43h Timer control word register, Timer control word register read back, and Counter
latch command
50h-53h Aliased at 40h-43h
61h NMI status and control register
70h NMI enable registerand Real-time clock (Standard RAM) index register
P20 Primary IDE connector
P21 Secondary IDE connector
P70 CPU fan connector
P200 Hood lock solenoid connector
SW50 Clear CMOS button
XBT1 Battery
XMM1-3 Memory sockets
XU1 Processor socket
P12 NIC SOS connector
P29 SCSI LED connetor
SW1 Security hood switch
IRQ System Function
8 Real-Time Clock
9 Unused
10 Unused, available for PCI
11 Unused, available for PCI
12 Mouse
13 Coprocessor
14 IDE interface hard drive
15 CD-ROM
DMA System Function
4 DMA Controller Cascading
5 Unused
6 Unused
7 Unused
ICH Fixed I/O Registers (Continued)
I/O Address (Hex) Register Name
71h Real-time clock (Standard RAM) target register
72h Extended RAM index register
73h Extended RAM target register
74h-75h Alaised at 70h-71h
76h-77h Aliased at 72h-73h or 70h-71h
81h, 82h, 83h Channel 2, 3, 1 DMA memory low page register
84h-86h, 88h Reserved page registers
89h, 8Ah, 8Bh Channel 6, 7, 5 DMA memory low page register
8Ch-8Eh Reserved page registers
8Fh Refresh low page register
91h-9Fh (except 92h) Aliased at 81h-8Fh
92h Fast A20 and INIT register
CF9h Reset control register
A0h Slave PIC ICW1 Init. cmd word 1 register, Slave PIC OCW2 Init. cmd word 2 reg-
ister, and Slave PIC 0CW3 Init. cmd word 3 register
A1 Slave PIC ICW2 Init. cmd word 2 register, Slave PIC ICW3 Init. cmd word 3 regis-
ter, Slave PIC ICW4 Init. cmd word 4 register, and Slave PIC OCW1 Init. cmd
word 1 register
A4h-A5h, A8h-A8h, ACh-ADh, Aliased at A0h-A1h
B0h-B1h, B4h-B5h, B8h-B9h,
BCh-Bdh
B2h Advanced power management control port register
B3h Advanced power management status port register
C0h, C4h, C8h, CCh Channel 4, 5, 6, 7 DMA base and current address register
C1h Aliased at C0h
C5h Aliased atC4h
C9h Aliased at C8h
CDh Aliased at CCh
C2h, C6h, CAh, CEh Channel 4, 5, 6, 7 DMA base and current count register
C3h Aliased at C2h
C7h Aliased at C6h
CBh Aliased at CAh
CFh Aliased at Ceh
D0h Channel 4-7 DMA command register and status register
D1h Aliased at D0h
D4h Channel 4-7 DMA write single mask register
D5h Aliased at D4h
D6h Channel 4-7 DMA channel mode register
D7h Aliased at D6h
D8h Channel 4-7 DMA clear byte pointer register
D9h Aliased at D8h
DAh Channel 4-7 DMA master clear register
DBh Aliased at DAh
DCh Channel 4-7 DMA clear mask register
DEh Aliased at DCh
DEh Channel 4-7 DMA write all mask register
DFh Aliased at DEh
F0h Coprocessor error register
170h-177h PIO mode command block offset for secondary drive
1F0h-1F7h PIO mode command block offset for primary drive
376h PIO mode control block offset for secondary drive
3F6h PIO mode control block offset for primary drive
4D0h Master PIC edge/level triggered register
3F6h PIO mode control block offset for primary drive
4D1h Slave PIC edge/level triggered register
400-47F Super I/O
F800-F87F Reserved (power management)
FA00-FA3F Reserved (GPIO management)
FC00-FC0F Reserved (SMBUS controller)
NOTE: When the POS_DEC_EN bit is set, additional I/O ports get positively decoded by the ICH.
System Memory Map
Size Memory Address
512 KB FFFFFFFFh to FFF80000h
3839 MB FFFBFFFFh to 10000000h
511 MB 0FFFFFFFh to 00100000h
128 KB 000FFFFFh to 000E0000h
96 KB 000DFFFFh to 000C8000h
32 KB 000C7FFFh to 000C0000h
128 KB 000BFFFFh to 000A0000h
640 KB 0009FFFFh to 00000000h
Clearing CMOS*
The computer's configuration (CMOS) may occasionally be corrupted. If it is, it is necessary to clear the CMOS
memory using switch SW50.
To clear and reset the configuration, perform the following procedure:
1. Prepare the computer for disassembly.
Ä
CAUTION: The power cord must be disconnected from the power source before pushing the Clear CMOS
Button (NOTE: All LEDs on the board should be OFF). Failure to do so may damage the system board
2. Remove the access panel.
3. Press the CMOS button located on the system board and keep it depressed for 5 seconds.
4. Replace the access panel.
5. Turn the computer on and run F10 Computer Setup (delete-utility) to reconfigure the system.
*When the CMOS button is pushed or the jumper is removed, both the power-on password and the setup password
become invalid because both are stored in the configuration memory. You will neet to reset the passwords.
Disabling or Clearing the Power-On and Setup Passwords*
1. Turn off the computer and any external devices, and disconnect the power cord from the power outlet.
2. Remove the access panel.
3. Locate the header and jumper labeled E49.
4. Remove the jumper from pins 1 and 2. Place the jumper over pin 2 only, in order to avoid losing it.
5. Replace the access panel.
6. Plug in the computer and turn on power. Allow the operating system to start.
NOTE: Placing the jumper on pin 2 clears the current passwords and disables the password features.
7. To re-enable the password features, repeat steps 1-3, then replace the jumper on pins 1 and 2.
8. Repeat steps 5-6, then establish new passwords.
Refer to the Computer Setup (F10 Setup) instructions to establish new passwords.
*When the CMOS button is pushed or the jumper is removed, both the power-on password and the setup password
become invalid because both are stored in the configuration memory. You will neet to reset the passwords.
System Function
System ROM
PCI memory expansion
Host or PCI memory expansion
System ROM
PCI option ROMs
Video ROM
Video RAM
Base memory