KSZ8841-16 Micrel Semiconductor, KSZ8841-16 Datasheet - Page 49

• Manufacturer Part Number: KSZ8841-16
• Description: Single-port Ethernet Mac Controller With Non-pci Interface
• Manufacturer: Micrel Semiconductor

Bank 3 On-Chip Bus Control Register (0x00): OBCR
This register controls the on-chip bus speed for the KSZ8841M. It is used for power management when the external host
CPU is running at a slow frequency. The default of the on-chip bus speed is 125 MHz without EEPROM. When the
external host CPU is running at a higher clock rate, the on-chip bus should be adjusted for the best performance.
Bank 3 EEPROM Control Register (0x02): EEPCR
To support an external EEPROM, tie the EEPROM Enable (EEEN) pin to High; o
EEPROM is not used, the default chip Base Address (0x300), and the software programs the host MAC address. If an
EEPROM is used in the design (EEPROM Enable pin to High), the chip Base Address and host MAC address are loaded
f
directly; that is, the EEPROM acce
set.
November 2005
rom th
Micrel Confidential
Bit
15-2
1-0
Bit
15-5
4
3
2-0
e E
EP
Default Value
-
0x0
Default Value
-
0
-
0x0
ROM immedi
ately
R/W
RO
RW
R/W
RO
RW
RO
RW
aft
er reset. The KSZ8841M a
ss timing can be fully controlled by the softw
Description
Reserved.
OBSC On-Chip Bus Speed Control
00: 125MHz.
01: 62.5MHz.
10: 41.66MHz.
11: 25MHz.
Note: When external EEPROM is enabled, the bit 1 in Configparm word (0x6H) is
used to contol this speed as below:
Bit 1 = 0 , this value will be 00 for 125 MHz.
Bit 1 = 1 , this value will be 11 for 25 MHz.
(User still can write these two bits to change speed after EEPROM data loaded)
Description
Reserved.
EESA EEPROM Software Access
1: enable software to access EE
0: disable software to access EEPROM
EECB EEPROM Status Bit
Data Receive from EEPROM
EECB EEPROM Control Bits
Bit 2: Data Transmit to EEPROM. This bit directly controls the device’s EEDO pin.
Bit 1: Serial Clock. This bit di
Bit 0: Chip Select for EEPROM. This bit directly controls the device’s EECS pin.
49
rectly controls the device’s EESK pin.
. This bit directly reads the EEDI pin.
llows the software to access (read and write) the EEPROM
PROM through bit 3 to bit 0.
.
are if the EEPROM Software Access bit is
therwise, tie it to Low. If an external
KSZ8841-16/32 MQL/MVL
Rev 1.3