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8XC196NT USER'S MANUAL
15.7.2 Power-up and Power-down Sequences
When you are ready to begin programming, follow these power-up and power-down procedures.
Failure to observe these warnings will cause permanent device damage.
•
Voltage must not be applied to V
•
The V
voltage must be within 1 volt of V
PP
go above 4.5 volts until V
•
The V
maximum voltage must not be exceeded.
PP
•
EA# must reach programming voltage before V
•
The PMODE pins (P0.7:4) must be in their desired states before RESET# rises.
•
All voltages must be within the ranges specified in the datasheet and the oscillator must be
stable before RESET# rises.
•
The power supplies to the V
of glitches and spikes.
•
All V
pins must be well grounded.
SS
15.7.2.1
Power-up Sequence
1.
Hold RESET# low while V
2.
After V
and the oscillator stabilize, continue to hold RESET# low and apply V
CC
to EA#.
3.
After EA# stabilizes, apply V
4.
Set the PMODE value to select a programming algorithm.
5.
Bring the RESET# pin high.
6.
Complete the selected programming algorithm.
15.7.2.2
Power-down Sequence
1.
Assert the RESET# signal and hold it low throughout the powerdown sequence.
2.
Remove the V
PP
3.
Remove the V
PP
4.
Turn off the V
CC
15-14
WARNING
while V
PP
is at least 4.5 volts.
CC
, V
, EA# and RESET# pins must be well regulated and free
CC
PP
stabilizes. Allow V
CC
voltage (+12.5V) to the V
PP
voltage from the V
pin and allow the pin to float.
PP
voltage from the EA# pin and allow the pin to float.
supply and allow time for it to reach 0 volts.
is low.
CC
while V
is less than 4.5 volts. V
CC
CC
does so.
PP
and EA# to float during this time.
PP
pin.
PP
must not
PP
voltage
PP
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