KL5KUSB121

USB to 10/100 Ethernet Controller

Kawasaki LSI

9

Ver. 1.1

PRELIMINARY

AC CHARACTERISTICS

U2E chip has 4 types of interfaces – USB port, Ethernet PHY port, SRAM

port and Serial EEPROM port. AC timing of these interfaces are described

below along with appropriate timing charts. Chip also requires the AC timing

of system clock input CLKI and system reset RESETN.

1. CLKI and RESETN Signal

Figure 1.1 CLKI and RESETN AC Timing

Table 1.1 CLKI AC Characteristics (over recommended range)

Symbol

Parameter

Min

Typ

Max

Unit

Not

e

Tpck

CLKI one cycle time

–

20.83

–

ns

1

Fck

CLKI frequency

–

48

–

MH

z

1

Tckh

CLKI high time

10

–

–

ns

1

Tckl

CLKI low time

10

–

–

ns

1

Note: 1) The clock is used as an USB sampling clock and to

generate the internal 32MHz clock pulse.

Table 1.2 RESETN AC characteristics (over recommended range)

Symbol

Parameter

Min

Typ

Max

Unit

Not

e

Tprst

RESETN low pulse

width

10

–

–

Tpc

k

2

Note: 2) RESETN is an asynchronous, low assert, reset signal.

Minimum assertion is 10 times of Tpck (210 ns).

2. USB Interface

The USB signals – VP and VM are the pair signals of the differential output driver and

receiver. The USB to Ethernet operates under USB Full speed (12Mb/s).

USB signals are fully compatible with USB spec rev 1.1.

Tpck

Tckh

Tckl

CLKI

(IN)

Tprst

RESETN

(IN)