KSZ8999 Micrel Inc, KSZ8999 Datasheet - Page 28

• Manufacturer Part Number: KSZ8999
• Description: IC SWITCH 10/100 9PORT 208PQFP
• Manufacturer: Micrel Inc

Specifications of KSZ8999

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 208-MQFP, 208-PQFP
• Fiber Support: Yes
• Integrated Led Drivers: Yes
• Phy/transceiver Interface: MII/SNI
• Power Supply Type: Analog/Digital
• Package Type: PQFP
• Data Rate (typ): 10/100Mbps
• Vlan Support: Yes
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Mounting: Surface Mount
• Jtag Support: No
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 576-1644 - BOARD EVALUATION FOR KSZ8999
• Lead Free Status / RoHS Status: Compliant, Lead free / RoHS Compliant
• Other names: 576-1044

January 2005
Micrel, Inc.
Optional CPU Interface
Instead of using an EEPROM to program the KS8999, one can use an external processor. To utilize this feature, the
CFGMODE pin (only available on the 208 pin package) needs to pulled low. This makes the KS8999 serial and clock
interface into a slave rather than a master. In this mode, clock and data are sourced from the processor.
Due to timing constraints, the maximum clock speed that the processor can generate is 8MHz. Data timing is
referenced to the rising edge of the clock and are 10ns for setup and 60ns for hold. The processor needs to supply
the exact number of clock cycles and data bits to program the KS8999 properly. KS8999 won’t start until all of the
registers are programmed. Bits are loaded from high order (bit 7) to low order (bit 0) starting with register 0 and
finishing with register 53.
Register 0: Skip clock on first bit 7
Register 1 to Register 53: provide clock on bit 7 to bit 0
28
SCL clock cycle: 7
SCL clock cycle: 424
Total SCL clock cycle: 431
KS8999
KS8999