Intel 8XC196MD Benutzerhandbuch
8XC196MC, MD, MH USER’S MANUAL
16-14
16.7.2 Power-up and Power-down Sequences
When you are ready to begin programming, follow these power-up and power-down procedures.
WARNING
Failure to observe these warnings will cause permanent device damage.
•
Voltage must not be applied to V
PP
while V
CC
is low.
•
The V
PP
voltage must be within 1 volt of V
CC
while V
CC
is less than 4.5 volts. V
PP
must not
go above 4.5 volts until V
CC
is at least 4.5 volts.
•
The V
PP
maximum voltage must not be exceeded.
•
EA# must reach programming voltage before V
PP
does so.
•
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.
stable before RESET# rises.
•
The power supplies to the V
CC
, V
PP
, EA# and RESET# pins must be well regulated and free
of glitches and spikes.
•
All V
SS
pins must be well grounded.
16.7.2.1
Power-up Sequence
1.
Hold RESET# low while V
CC
stabilizes. Allow V
PP
and EA# to float during this time.
2.
After V
CC
and the oscillator stabilize, continue to hold RESET# low and apply V
PP
voltage
to EA#.
3.
After EA# stabilizes, apply V
PP
voltage (+12.5V) to the V
PP
pin.
4.
Set the PMODE value to select a programming algorithm.
5.
Bring the RESET# pin high.
6.
Complete the selected programming algorithm.
16.7.2.2
Power-down Sequence
1.
Assert the RESET# signal and hold it low throughout the powerdown sequence.
2.
Remove the V
PP
voltage from the V
PP
pin and allow the pin to float.
3.
Remove the V
PP
voltage from the EA# pin and allow the pin to float.
4.
Turn off the V
CC
supply and allow time for it to reach 0 volts.