w89c926 Winbond Electronics Corp America, w89c926 Datasheet - Page 18

• Manufacturer Part Number: w89c926
• Description: Pcmcia Ethernet Network Twisted Pair Interface Controller
• Manufacturer: Winbond Electronics Corp America

EEPROM Address/Data Register (ADR)
This register is located on page 3 and is used for EEPROM address or data transfer during EEPROM
access.
Access Address: IOBase + 04H
Access Type: I/O Read/Write
POWER-ON INITIALIZATION AND AUTO-LOADING PROCESS
When powered on, the system should reset the card first, as required by the PCMCIA specifications.
The reset signal will trigger a number of internal operations: First, the PENTIC+ monitors the
EECS/FCS pin to determined where the configurations are stored. If this pin is pulled high, the
configurations are stored in the flash memory; if it is pulled low, they are stored in an EEPROM.
Then, within 10ms after the reset pulse is negated, the PENTIC+ will automatically load the
configurations, ID, and CIS data into the LAN configuration registers and the upper half of SRAM (if
an EEPROM is used). During this auto-load procedure the PENTIC+ will assert IREQ low for
Rdy/Bsy signaling, since the socket is configured at the memory-only interface during initialization.
Note that this auto-load operation occurs only after a hardware reset pulse. A software reset
(including setting COR.SRESET = 1) will not invoke this operation.
EECS/FCS Pulled High
If EECS/ FCS is pulled high, this indicates that the configurations are stored in a flash memory.
Accordingly, after a power-on reset the PENTIC+ will automatically load the LAN configuration
registers from flash memory. The Ethernet IDs stored in the flash memory will be mapped into ID
registers automatically when they are read.
BIT
0-5
6
7
SYMBOL
EW/ ER
EOS
-
Reserved. Must be 0s.
EEPROM Write/Read Select.
This bit selects the EEPROM read/write sequence. If EW/ER = 1, the
write sequence is selected. If EW/ER = 0, the read sequence is selected.
EEPROM Operation Select.
This bit enables the EEPROM read/write sequence. If EOS = 1, the
EEPROM read/write sequence will be started. EOS is reset if the
read/write sequence is finished or aborted.
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DESCRIPTION
W89C926 PENTIC+