46 www.national.com
DP83847
6.1 Reset Timing
Note1: Software Reset should be initiated no sooner then 500 µs after power-up or the deassertion of hardware reset.
Note2: It is important to choose pull-up and/or pull-down resistors for each of the hardware configuration pins that provide
fast RC time constants in order to latch-in the proper value prior to the pin transitioning to an output driver.
Parameter Description Notes Min Typ Max Units
T1.0.1 Post RESET Stabilization time
prior to MDC preamble for reg-
ister accesses
MDIO is pulled high for 32-bit serial man-
agement initialization.
3 µs
T1.0.2 Hardware Configuration Latch-
in Time from the Deassertion of
RESET (either soft or hard)
Hardware Configuration Pins are de-
scribed in the Pin Description section.
3 µs
T1.0.3 Hardware Configuration pins
transition to output drivers
3.5 µs
T1.0.4 RESET pulse width X1 Clock must be stable for at min. of
160us during RESET pulse low time.
160 µs
V
CC
HARDWARE
RSTN
MDC
32 CLOCKS
Latch-In of Hardware
Configuration Pins
Dual Function Pins
Become Enabled As Outputs
INPUT
OUTPUT
T1.0.3
T1.0.2
T1.0.1
T1.0.4
X1 Clock
