83C51KB Datasheet, PDF (18/19 Pages) Intel Corporation – HIGH PERFORMANCE KEYBOARD MICROCONTROLLER

83C51KB HIGH PERFORMANCE KEYBOARD MICROCONTROLLER
6.5 External Data Memory Read Cycle External Data Memory Write Cycle Waveform
ALE
PSEN#
WR#
PORT 0
PORT 2
T_LHLL
T_WHLH
T_LLWL
T_RLWH
T_AVLL
T_LLAX
A0-A7 from RI or DPL
T_AVWL
T_QVWX
T_QVWH
Data Out
P2.0 - P2.7 or A8 - A15 from DPH
T_WHQX
A0 - A7 from PCL
Instr. In
A8 - A15 from PCH
A4256-01
Figure 6. External Data Memory Write Cycle
6.6 Testing Characteristics
V_LOAD + 0.1 V
V_LOAD
V_LOAD – 0.1 V
Timing Reference
Points
V_OH – 0.1 V
V_OL + 0.1 V
For timing purposes, a port pin is no longer floating when a
100 mV change from load voltage occurs and begins to float
when a 100 mV change from the loading V_OH/V_OL level occurs
with I_OL/I_OH = ± 20 mA.
Figure 7. Float Waveforms
A4243-01
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