MOTOROLA
Chapter 21. CDR3 Flash (UC3F) EEPROM
21-15
Programming Model
Figure 21-5. PEGOOD Valid Time
30
SES
Start-end program or erase sequence. The SES bit is write protected by the STOP, HVS, and
EHV bits. The SES bit is used to signal the start and end of a program or erase sequence. At the
start of a program or erase sequence, SES is set. This will lock STOP, PROTECT, SBPROTECT,
BLOCK, SBBLOCK, SBEN, CSC, and PE. If PE = 0 and SES = 1, SIE will be write locked. At this
point, the UC3F EEPROM is ready to receive either the programming writes or the erase
interlock write.
NOTE: The erase interlock write is a write to any UC3F EEPROM array location after SES is set
and PE = 1.
If PE = 0 and SES = 1, writes to the UC3F array are programming writes. The first programming
write sets the address of the location to be programmed, and the data written is captured into the
program data latch for programming into the UC3F array. All programming writes after the first
programming write update the program data latch but do not change the address to be
programmed.
At the end of the program or erase operation, the SES bit must be cleared to return to normal
operation and release the STOP, PROTECT, SBPROTECT, BLOCK, SBBLOCK, CSC, SBEN,
and PE bits.
0 UC3F EEPROM not configured for program or erase operation
1 Configure UC3F EEPROM for program or erase operation
31
EHV
Enable high voltage. EHV can be asserted only after the SES bit has been asserted and a valid
programming write(s) or erase hardware interlock write has occurred. If an attempt is made to
assert EHV when SES is negated, or if a valid programming write or erase hardware interlock
write has not occurred since SES was asserted, EHV will remain negated.
The external program or erase enable pin (EPEE) and EHV are used to control the application
of the program or erase voltage to the UC3F EEPROM module. High voltage operations to the
UC3F EEPROM array, special shadow locations or FLASH NVM registers can occur only if
EHV = 1 and EPEE = 1.
Only after the correct hardware and software interlocks have been applied to the UC3F
EEPROM can EHV be set. Once EHV is set, SES cannot be changed and attempts to read the
array will not be acknowledged.
Clearing EHV during a program or erase operation will safely terminate the high voltage
operation. If EHV is cleared while using the embedded hardware program/erase algorithm, the
program/erase routine will abort the operation and exit normally.
0 Program or erase pulse disabled
1 Program or erase pulse enabled
Table 21-5. UC3FCTL Bit Descriptions (continued)
Bits
Name
Description
PEGOOD
Valid Time
PEGOOD
Valid Time
PEGOOD
HVS
EHV
SES