Compaq D310 manual DMA Channel Controllers, Bios Overview Address Ports Function

BIOS Overview

	I/O Address Ports	Function
0000	- 000F	DMA controller 1
0020	- 0021	Master interrupt controller (8259)
002E - 002F		NS360 Configuration registers
0040	- 0043	Timer 1
0060, 0064		Keyboard controller (reset, slow A20)
0061		Port B (speaker, NMI status and control)
0070		Bit 7: NMI mask register
0070	- 0071	RTC and CMOS data
0080		Manufacturing port (POST card)
0081	- 0083, 008F	DMA low page register
0092		PS/2 reset and Fast A20
00A0 - 00A1		Slave interrupt controller
00C0 - 00DF		DMA controller 2
00F0 - 00FF		Co-processor error
0170	- 0177	IDE secondary channel
01F0 - 01F7		IDE primary channel
0278	- 027F	LPT 2
02E8 - 02EF		Serial port 4 (COM4)
02F8 - 02FF		Serial port 2 (COM2)
0372	- 0377	IDE secondary channel, secondary floppy disk drive
0378	- 037A	LPT1
03B0 - 03DF		VGA
03E8 - 03EF		COM3
03F0h- 03F5		Floppy disk drive controller
03F6		IDE primary channel
03F7		Floppy disk drive controller
03F8 - 03FF		COM1
04D0 - 04D1		Interrupt edge/level control
0678	- 067B	LPT2 ECP
0778	- 077B	LPT1 ECP
0CF8 - 0CFF		PCI configuration space

DMA Channel Controllers

Only “I/O-to-memory” and “memory-to-I/O” transfers are allowed. “I/O-to-I/O” and “memory-to-memory” transfers are disallowed by the hardware configuration.

The system controller supports seven DMA channels, each with a page register used to extend the addressing range of the channel to 16 MB. The following table summarizes how the DMA channels are allocated.

Evo D310 Micro Desktop 45