KSZ8995FQI Datasheet, PDF (44/89 Pages) Micrel Semiconductor – Integrated 5-Port 10/100 Managed Switch

Micrel, Inc.
To use the KS8995MA/FQ SPI:
1. At the board level, connect KS8995MA/FQ pins as follows:
KS8995MA/FQ
KS8995MA/FQ Pin Number
112
110
111
109
KS8995MA/FQ Signal Name
SPIS_N
SPIC
SPID
SPIQ
Microprocessor Signal Description
SPI Slave Select
SPI Clock
Master Out Slave Input
Master In Slave Output
Table 9. 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 KS8995MA/FQ 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 KS8995MA/FQ operation.
SPIS_N
SPIC
SPID
SPIQ
X 0 0 0 0 0 0 1 0 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
WRITE COMMAND
WRITE ADDRESS
Figure 9. SPI Write Data Cycle
WRITE DATA
SPIS_N
SPIC
SPID
SPIQ
X 0 0 0 0 0 0 1 1 A7 A6 A5 A4 A3 A2 A1 A0
D7 D6 D5 D4 D3 D2 D1 D0
READ COMMAND
READ ADDRESS
Figure 10. SPI Read Data Cycle
READ DATA
October 2011
44
M9999-102611-3.0