CS8900A
Crystal LAN™ ISA Ethernet Controller
4.3.3 Interrupt Number
(Read/Write, Address: PacketPage base + 0022h)
Address 0023h
Address 0022h
Interrupt number assignment:
0000 0000b= pin INTRQ0
0000 0001b= pin INTRQ1
0000 0010b= pin INTRQ2
00h
0000 0011b= pin INTRQ3
0000 01XXb= All INTRQ pins high-impedence
The Interrupt Number Register defines the interrupt pin selected by the CS8900A. In a typical application the follow-
ing bus signals are tied to the following pins:
Bus signal
IRQ5
Typical pin connection
INTRQ3
IRQ10
IRQ11
INTRQ0
INTRQ1
IRQ12
INTRQ2
See Section 3.2 on page 18.
After reset, if no EEPROM is found by the CS8900A, then the register has the following initial state, which corre-
sponds to placing all the INTRQ pins in a high-impedance state. If an EEPROM is found, then the register’s initial
value may be set by the EEPROM. See Section 3.3 on page 19.
Reset value is: XXXX XXXX XXXX X100
4.3.4 DMA Channel Number
(Read/Write, Address: PacketPage base + 0024h)
Address 0025h
00h
Address 0024h
DMA channel assignment:
0000 0000b= pin DMRQ0 and DMACK0
0000 0001b= pin DMRQ1 and DMACK1
0000 0010b= pin DMRQ2 and DMACK2
0000 0011b= All DMRQ pins high-impedence
The DMA Channel register defines the DMA pins selected by the CS8900A. In the typical application, the following
bus signals are tied to the following pins:
Bus signal
DRQ5
Typical pin connection
DMRQ0
DACK5
DMACK0
DRQ6
DMRQ1
DACK6
DRQ7
DMACK1
DMRQ2
DACK7
DMACK2
See Section 3.2 on page 18 and Section 5.4 on page 90.
After reset, if no EEPROM is found by the CS8900A, then the register has the following initial state which corre-
sponds to setting all DMRQ pins to high-impedance. If a EEPROM is found, then the register’s initial value may be
set by the EEPROM. See Section 3.3 on page 19.
Reset value is: XXXX XXXX XXXX XX11
CIRRUS LOGIC PRODUCT DATA SHEET
DS271PP3
43
CIRRUS [ CIRRUS LOGIC ]
