w89c840af Winbond Electronics Corp America, w89c840af Datasheet - Page 61

• Manufacturer Part Number: w89c840af
• Description: 100/10mbps Ethernet Controller
• Manufacturer: Winbond Electronics Corp America

C28/CBROA Boot ROM Offset Address Register
The register C28/CBROA is used to specify the read or write address of the external boot ROM when accessing the
boot ROM through the register C24/CMIIR of the W89C840AF .
C2C/CGTR General Timer Register
The C2C/CGTR shows the real time content of the W89C840AF
3:0
Bit
31:18
17:0
Bit
31:17
16
R/W
Attribute
R
R/W
Attribute
R
R/W
EEBRD
[33:0]
Bit name
---
BROA
Bit name
---
RECUR
EEPROM/Boot ROM Data 0 to 3:
The EEBRD[3:0] are used to store the read/write data for the on-
board boot ROM access when EESEL is reset to low.
When EESEL is set to high,
1) the EEBRD[3] reflects the input data from the BtAdata3/EEDO
pin(connected to EEPROM data output) instantly.
2) the EEBRD[2] stores the output data which will be drove onto
the BtAdata2/EEDI pin(connected to EEPROM data input) directly.
3) the EEBRD[1] stores the output data which will be drove onto
the BtAdata1/EECK pin (EEPROM serial clock input) directly.
4) the EEBRD[0] stores the output data which will be drove onto
the EECS pin(connected to EEPROM chip select) directly.
For accessing the external EEPROM device, the chip select signal,
the serial clock and the data input should follow the AC
specification defined by the external EEPROM device.
Description
Reserved. Fixed at 0.
Boot ROM Offset Address.
This field contains boot ROM offset address.
Description
Reserved. Fixed at 0.
Recursive Mode:
The state of the bit 0 to bit 15 in the register C2C/CGTR will be set
to the states programmed by the driver program at the last time
when the TIME timer count reaching zero if the RECUR is set to
high. Default 0.
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Publication Release Date:October 2000
Revision 1.01
internal general timer
W89C840AF