CS8900A
Crystal LAN™ Ethernet Controller
EECS - EEPROM Chip Select, PIN 3.
Active-high output used to select the EEPROM.
EEDataIn - EEPROM Data In, Input Internal Weak Pullup PIN 6.
Serial input used to receive data from the EEPROM. Connects to the DO pin on the
EEPROM. EEDataIn is also used to sense the presence of the EEPROM.
ELCS - External Logic Chip Select, Internal Weak Pullup PIN 2.
Bi-directional signal used to configure external Latchable Address (LA) decode logic. If
external LA decode logic is not needed, ELCS should be tied low.
EEDataOut - EEPROM Data Out, PIN 5.
Serial output used to send data to the EEPROM. Connects to the DI pin on the
EEPROM. When TEST is low, this pin becomes the output for the Boundary Scan
Test.
CSOUT - Chip Select for External Boot PROM, PIN 17.
Active-low output used to select an external Boot PROM when the CS8900A decodes
a valid Boot PROM memory address.
10BASE-T Interface
TXD+/TXD- - 10BASE-T Transmit, Differential Output Pair PINS 87 and 88.
Differential output pair drives 10 Mb/s Manchester-encoded data to the 10BASE-T
transmit pair.
RXD+/RXD- - 10BASE-T Receive, Differential Input Pair PINS 91 and 92.
Differential input pair receives 10 Mb/s Manchester-encoded data from the 10BASE-T
receive pair.
Attachment Unit Interface (AUI)
DO+/DO- - AUI Data Out, Differential Output Pair PINS 83 and 84.
Differential output pair drives 10 Mb/s Manchester-encoded data to the AUI transmit
pair.
DI+/DI- - AUI Data In, Differential Input Pair PINS 79 and 80.
Differential input pair receives 10 Mb/s Manchester-encoded data from the AUI receive
pair.
CI+/CI- - AUI Collision In, Differential Input Pair PINS 81 and 82.
Differential input pair connects to the AUI collision pair. A collision is indicated by the
presence of a 10 MHz ± 15% signal with duty cycle no worse than 60/40.
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