DP83902A datasheet(64/70 Pages) NSC

64 / 70 page

150 Switching Characteristics AC Specs DP83902A Note All Timing is Preliminary (Continued)

Remote DMA (Write Cycle) Recovery Time

TLF11157 – 45

Symbol

Parameter

Min

Max

Units

bprqh

Bus Clock to Port Request High (Note 1)

wprql

WACK to Port Request Low

wackw

WACK Pulse Width

bprdl

Bus Clock to Port Read Low (Note 2)

bprdh

Bus Clock to Port Read High

wprq

Remote Write Port Request to Port

BSCK

Request Time (Notes 3 4 5)

Note 1

The first port request is issued in response to the remote write command It is subsequently issued on T1 clock cycles following completion of remote DMA

cycles

Note 2

The start of the remote DMA write following WACK is dependent on where WACK is issued relative to BSCK and whether a local DMA is pending

Note 3

Assuming wackw k 1 BSCK and no local DMA interleave no CS immediate BACK and WACK goes high before T4

Note 4

WACK must be high for a minimum of 7 BSCK

Note 5

This is not a measured value but guaranteed by design

Reset Timing

TLF11157 – 64

Symbol

Parameter

Min

Max

Units

rstw

Reset Pulse Width (Note 1)

BSCK Cycles or TXC Cycles

(Note 2)

Note 1

The RESET pulse requires that BSCK and TXC be stable On power up RESET should not be raised until BSCK and TXC have become stable Several

registers are affected by RESET Consult the register descriptions for details

Note 2

The slower of BSCK or TXC clocks will determine the minimum time for the RESET signal to be low

If BSCK k TXC then RESET e 8 c BSCK

If TXC k BSCK then RESET e 8 c TXC

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