COM20051I Datasheet, PDF (68/74 Pages) SMSC Corporation – Integrated Microcontroller and ARCNET (ANSI 878.1) Interface

TIMING DIAGRAMS
AC CHARACTERISTICS (0°C - 70°C, 5.0V ± 10%)
100 pF Loading for ALE, PORT0, and nPSEN; 16 MHz Processor Clock
ALE
nPSEN
PORT 0
t7
t1
t8
t3
t10
t2
t5
t4
t9
t6
A0 - A7
t11
INSTR. IN
PORT 2
A8 - A15
Parameter
t1
ALE Pulse Width
t2
Address Valid to ALE Low
t3
ALE Low to nPSEN Low
t4
nPSEN Low to Valid Instruction Input
t5
nPSEN Low to Address Float
t6
Address to Valid Instruction Input
t7
Address Hold after ALE
t8
ALE Low to Valid Instruction Input
t9
nPSEN Pulse Width
t10
Input Instruction Hold after nPSEN
t11
Input Instruction Float after nPSEN
min
85
7
22.6
27
142.5
0
typ max units
nS
nS
nS
82.5 nS
10
nS
207.5 nS
nS
150
nS
nS
nS
37.5 nS
FIGURE 24 – EXTERNAL PROGRAM MEMORY READ CYCLE
SMSC DS – COM20051I
Page 68
Rev. 03/27/2000