KSZ8895 INFINEON [Infineon Technologies AG], KSZ8895 Datasheet - Page 39

• Manufacturer Part Number: KSZ8895
• Description: Integrated 5-Port 10/100 Managed Ethernet Switch with MII/RMII interface
• Manufacturer: INFINEON [Infineon Technologies AG]

Micrel, Inc.
PHY, if the device interfacing with the KSZ8895MQ/RQ/FMQ has an MTXER pin, it should be tied low.
Port 5 MAC 5 Switch SW5-RMII Interface for the KSZ8895RQ
The Reduced Media Independent Interface (RMII) specifies a low pin count Media Independent Interface (MII). The
KSZ8895RQ supports RMII interface at Port 5 switch side and provides a common interface at MAC5 layer in the
device, and has the following key characteristics:
KSZ8895RQ supports MAC5 RMII interfaces at the switch side:
When the device is strapped to normal mode by pin LED2_2 pull-down, the reference clock comes from SMTXC
which will be as device’s clock source. The external 25MHz crystal clock from pins X1/X2 will be ignored.
Note: In the normal mode, the 50MHz clock from SMTXC will be as the clock source for whole device. The PHY5
PMTXC/PMREFCLK pin can not be used as the clock source for whole device, the pin of PMTXC/PMREFCLK can
receive the 50MHz clock from PMRXC when device is strap to normal mode and external 50MHz reference clock
comes in from pin SMTXC. In the normal mode, the 50MHz clock on pin SMRXC can be disabled by register, the
PMRXC 50MHz clock can be used when P5-RMII interface is used also.
There is a register 12 bit 6 to monitor the status of the device for the clock mode or normal mode.
When use an external 50MHz clock source as RMII reference clock, the KSZ8895RQ should be set to normal mode
by pull-down its LED2_2 strap-in pin first before power up reset or worm reset. The normal mode of KSZ8895RQ
device will be start to work when get the 50MHz reference clock from pin SMTXC/SMREFCLK by an external 50MHz
clock source. For the RMII connection examples, please refer to app note in the desigh kit.
January 2011
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Supports 10Mbps and 100Mbps data rates.
Uses a single 50 MHz clock reference (provided internally or externally): in internal mode, the chip provides
reference clock from SMRXC pin to SMTXC pin and provide the clock to the opposite clock input pin for RMII
interface; in external mode, the chip receives 50MHz reference clock from an external oscillator or opposite
RMII interface.
Provides independent 2-bit wide (bi-bit) transmit and receive data paths.
For the detail of SW5-RMII (Port 5 MAC5 RMII ) signals connection see the table below:
The KSZ8895RQ can provide a 50MHz reference clock for both MAC to MAC and MAC to PHY RMII
interfaces when SW5-RMII is used in the clock mode of the device (default with strap pin LED2_2 internal
pull-up for the clock mode).
The KSZ8895RQ also can receive 50MHz reference clock from external 50MHz clock source or opposite
RMII to SW5-RMII SMTXC pin when the device is set to normal mode (the strap pin LED2_2 is pulled down).
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KSZ8895MQ/RQ/FMQ
M9999-012011-1.2