KL5KUSB121

USB to 10/100 Ethernet Controller

Kawasaki LSI

13

Ver. 1.1

PRELIMINARY

4.2 SRAM Write Access

Figure 4.2.1 SRAM Write AC Timing

Table 4.2.1 SRAM Write AC Characteristics (over recommended range)

Symbol

Parameter

Min

Typ

Max

Unit

Not

e

Twc

SRAM write cycle

31.25

–

–

ns

1,2

Fwc

SRAM write frequency

–

–

32

MH

z

1,2

Tdaw

SRAMWEN assert

delay

from SRAMA valid

0

–

–

ns

2

Tdwa

SRAMA invalid delay

from SRAMWEN

negate

0

–

–

ns

2

Tdcw

SRAMWEN assert

delay

from SRAMCSN assert

0

–

–

ns

2

Tdwc

SRAMCSN negate

delay

from SRAMWEN

negate

0

–

–

ns

2

Tpwe

SRAMWEN low width

25

–

–

ns

2

Tdrv

SRAMD drive delay

from SRAMWEN

assert

0

–

–

ns

2

Tval

SRAMD valid

from SRAMWEN

assert

–

–

15

ns

2

Tts

SRAMD hold time

from SRAMWEN rise

0

–

–

ns

2

Note: 1) Same as the USB to Ethernet internal clock cycle time 1T (31.25 ns).

2) Outputs are assumed to have 30pF external capacitive load.

SRAMA14-0

(OUT)

SRAMOEN

(OUT)

SRAMCSN

(OUT)

SRAMWEN

(OUT)

SRAMD7-0

(OUT)

Tdwa

valid

Twc

valid

Tpwe

Tts

Tdaw

Tdcw

Tdwc

Tval

Tdrv