CS8900A
Crystal LAN™ ISA Ethernet Controller
After a reset, the ISA bus outputs INTRx and
DMARQx are 3-Stated, thus avoiding any interrupt
or DMA channel conflicts on the ISA bus at power-
up time.
PacketPage Register
Register Descriptions
Address
Contents
0020h
0300h
I/O Base Address*
0022h
XXXX XXXX Interrupt Number
XXXX X100
3.3.4 Initialization
After each reset (except EEPROM Reset), the
CS8900A checks the sense of the EEDataIn pin to
see if an external EEPROM is present. If EEDI is
high, an EEPROM is present and the CS8900A au-
tomatically loads the configuration data stored in
the EEPROM into its internal registers (see next
section). If EEDI is low, an EEPROM is not
present and the CS8900A comes out of reset with
the default configuration shown in Table 3.
0024h
0026h
XXXX XXXX DMA Channel
XXXX XX11
0000h
DMA Start of Frame
Offset
0028h
002Ah
002Ch
0030h
X000h
0000h
DMA Frame Count
DMA Byte Count
XXX0 0000h Memory Base Address
XXX0 0000h Boot PROM Base
Address
A low-cost serial EEPROM can be used to store
configuration information that is automatically
loaded into the CS8900A after each reset (except
EEPROM reset). The use of an EEPROM is op-
tional.
0034h
XXX0 0000h Boot PROM Address
Mask
0102h
0104h
0106h
0108h
010Ah
010Ch
010Eh
0110h
0112h
0114h
0116h
0118h
0003h
Register 3 - RxCFG
Register 5 - RxCTL
Register 7 - TxCFG
Register 9 - TxCMD
Register B - BufCFG
Reserved
0005h
0007h
0009h
The CS8900A operates with any of six standard
EEPROM’s shown in Table 4.
000Bh
Undefined
Undefined
Undefined
00013h
0015h
Reserved
Reserved
Register 13 - LineCTL
Register 15 - SelfCTL
Register 17 - BusCTL
Register 19 - TestCTL
0017h
0019h
* I/O base address is unaffected by Software Suspend mode.
Table 3. Default Configuration
EEPROM Type
‘C46 (non-sequential)
‘CS46 (sequential)
‘C56 (non-sequential)
‘CS56 (sequential)
‘C66 (non-sequential)
‘CS66 (sequential)
Size (16-bit words)
64
64
128
128
256
256
Table 4. Supported EEPROM Types
CIRRUS LOGIC PRODUCT DATA SHEET
20
DS271PP3
CIRRUS [ CIRRUS LOGIC ]
