MPC555
/
MPC556
CDR MoneT FLASH EEPROM
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
19-37
If EPEE = 1 when EHV is asserted, high voltage operations such as program or erase
are enabled. If EPEE = 0 when EHV is asserted, high voltage operations are disabled.
The EPEE pin uses a two-period clock synchronizer that switches the internal signal
CMF_EPEE after two consecutive constant values of EPEE, as shown in
. At first the value of CMF_EPEE is unknown, as the prior information for the EPEE
pin is not provided. One high or low clock of EPEE does not cause CMF_EPEE to
switch.
Figure 19-8 CMF_EPEE Timing Diagram
19.9.2 FLASH Program/Erase Voltage Conditioning
A voltage of at least (VDDL – 0.35 V) must be applied at all times to the VPP pins or
damage to the FLASH module can occur. FLASH modules can be damaged by power
on and power off VPP transients. VPP must not rise to programming level while VDDL
is below 1.0 volts, and must not fall below the minimum specified value while VDDL is
applied.
shows the VPP and VDDL operating envelope.
Clock
EPEE
CMF_EPEE
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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