Specifications

Micrel, Inc.
KSZ8895MQ/RQ/FMQ
To use the KSZ8895MQ/RQ/FMQ SPI:
1. At the board level, connect KSZ8895MQ/RQ/FMQ pins as follows:
KSZ8895MQ/RQ/FMQ
Pin Number
KSZ8895MQ/RQ/FMQ
Signal Name
Microprocessor Signal Description
112 SPIS_N SPI Slave Select
110 SPIC SPI Clock
111 SPID Master Out Slave Input
109 SPIQ Master In Slave Output
Table 10. SPI Connections
2. Set the input signals PS[1:0] (pins 113 and 114, respectively) to “10” to set the serial configuration to SPI slave
mode.
3. Power up the board and assert a reset signal. After reset wait 100µs, the start switch bit in Register 1 will be set
to ‘0’. Configure the desired settings in the KSZ8895MQ/RQ/FMQ before setting the start register to ‘1.'
4. Write configuration to registers using a typical SPI write data cycle as shown in Figure 9 or SPI multiple write as
shown in Figure 11. Note that data input on SPID is registered on the rising edge of SPIC.
5. Registers can be read and configuration can be verified with a typical SPI read data cycle as shown in Figure 10
or a multiple read as shown in Figure 12. Note that read data is registered out of SPIQ on the falling edge of
SPIC.
6. After configuration is written and verified, write a ‘1’ to Register 1 bit 0 to begin KSZ8895MQ/RQ/FMQ switch
operation.
SPIQ
SPIC
SPID
SPIS_N
0 0 0 0 0 0 1 0X
A7 A6 A5 A4 A3 A2 A1
A0
WRITE COMMAND WRITE ADDRESS WRITE DATA
D2 D0D1D3D4D5D6D7
Figure 14. SPI Write Data Cycle
SPIQ
SPIC
SPID
SPIS_N
0 0 0 0 0 0 1 1
X
A7 A6 A5 A4 A3 A2 A1
A0
D7 D6 D5 D4 D3 D2 D1 D0
READ COMMAND READ ADDRESS READ DATA
Figure 15. SPI Read Data Cycle
March 12, 2014
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Revision 1.7