Filter
Top Products
6–2 Interrupts and ISA Bus Addresses
ISA I/O Address Map
6.2 ISA I/O Address Map
Table 6–2 lists the AlphaPC 164LX ISA I/O space address mapping.
IRQ13 Available
IRQ14 EIDE
IRQ15 EIDE
1
The # symbol indicates an active low signal.
Table 6–2 ISA I/O Address Map
Range (hex) Usage
000-00F 8237 DMA #1
020-021 8259 PIC #1
040-043 8253 timer
060-061 Ubus IRQ12 and NMI control
070 CMOS RAM address and NMI mask register
080-08F DMA page registers
0A0-0A1 8259 PIC #2
0C0-0DF 8237 DMA #2
2F8-2FF Serial port—COM2
370-377 Secondary diskette (floppy)
3BC-3BF Parallel port—LPT1
3F0-3F7 Primary diskette (floppy)
3F8-3FF Serial port—COM1
800 FLASH_ADR19 register
801 AlphaPC 164LX configuration register
804-806 PCI interrupt registers
Table 6–1 ISA Interrupts (Continued)
Interrupt Number Interrupt Source