Specifications

Chapter 3 Hardware
22 Reference Manual CoreModule 720
I/O Address Map
Table 3-3 shows the I/O address map. These are DOS-level addresses. The OS typically hides these physical
addresses by way of memory management.
Table 3-3. I/O Address Map
Address (hex) Subsystem
0000-00F Primary DMA Controller0
0020-0021 Master Interrupt Controller
0040-0043 Programmable Interrupt Timer (Clock/Timer)
0060-006F Keyboard Controller
0070-007F CMOS RAM, NMI Mask Reg, RT Clock
0080-009F DMA Page Registers
00A0-00BF Slave Interrupt Controller
00C0-00DF Slave DMA Controller #2
00F0-00FF Math Coprocessor
02E8-02EF Serial Port 4 (COM3)
02F8-02FF Serial Port 2 (COM1)
03B0-03BB Video (monochrome)
03C0-03DF VGA
03E8-03EF Serial Port 3 (COM2)
03F8-03FF Serial Port 1 (COM0)
0400-041F SMBus Configuration Ports
0500-053F PCH GPIO Configuration Ports
0800-087F PCH Power Management Ports
0A79h ISA PnP Ports
0CF8-0CFF PCI bus Configuration Address and Data
NOTE 0A79h is the ISA PnP port used by the BIOS and an OS that supports this feature to
recognize ISA PnP (Plug and Play) cards.
The Intel I/O hub PCH EG20T does not support ISA DMA.