DS80C390_05 Datasheet, PDF (3/53 Pages) Dallas Semiconductor – Dual CAN High-Speed Microprocessor

DS80C390 Dual CAN High-Speed Microprocessor
AC ELECTRICAL CHARACTERISTICS—(MULTIPLEXED ADDRESS/DATA BUS)
(Note 10, Note 11)
PARAMETER
Oscillator Frequency
ALE Pulse Width
Port 0 Instruction Address or CE0–4
Valid to ALE Low
SYMBOL
1 / t_CLCL
CONDITIONS
External oscillator
External crystal
40MHz
MIN MAX
0
40
1
40
t_LHLL
t_AVLL
VARIABLE CLOCK
MIN
MAX
0
40
1
40
0.375 t_MCS
-5
0.125 t_MCS - 5
UNITS
MHz
ns
ns
Address Hold After ALE Low
t_LLAX1
0.125 t_MCS - 5
ns
ALE Low to Valid Instruction In
t_LLIV
0.625 t_MCS - 20 ns
ALE Low to PSEN Low
t_LLPL
0.125 t_MCS - 5
ns
PSEN Pulse Width
t_PLPH
0.5 t_MCS - 8
ns
PSEN Low to Valid Instruction In
t_PLIV
Input Instruction Hold After PSEN
t_PXIX
Input Instruction Float After PSEN
t_PXIZ
0.5 t_MCS - 20
ns
0
0
ns
0.25 t_MCS - 5
ns
Port 0 Address to Valid Instruction In
Port 2, 4 Address to Valid Instruction
In
PSEN Low to Address Float
t_AVIV1
t_AVIV2
t_PLAZ
0.75 t_MCS - 22 ns
0.875 t_MCS - 30 ns
0
0
ns
Note 11:
All parameters apply to both commercial and industrial temperature operation unless otherwise noted. The value t_MCS is a function
of the machine cycle clock in terms of the processor’s input clock frequency. These relationships are described in the Stretch Value
Timing table. All signals characterized with load capacitance of 80pF except Port 0, ALE, PSEN, RD, and WR with 100pF.
Interfacing to memory devices with float times (turn off times) over 25ns can cause bus contention. This does not damage the
parts, but causes an increase in operating current. Specifications assume a 50% duty cycle for the oscillator. Port 2 and ALE timing
changes in relation to duty cycle variation. Some AC timing characteristic drawings contain references to the CLK signal. This
waveform is provided to assist in determining the relative occurrence of events and cannot be used to determine the timing of
signals relative to the external clock. AC timing is characterized and guaranteed by design but is not production tested.
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