MOTOROLA
Chapter 21. CDR3 Flash (UC3F) EEPROM
21-23
UC3F Operation
21.3.6
High Voltage Operations
There are two fundamental high voltage operations, program and erase. Program changes
a UC3F array bitcell from a logic 1 state to a logic 0 state and is a selective operation
performed on up to 32 bits at a time. Erase changes a UC3F array bitcell from a logic 0 state
to a logic 1 state and is a bulk operation performed on one block or multiple blocks of the
UC3F array.
21.3.6.1 Overview of Program/Erase Operation
The embedded hardware program/erase algorithm relies on an internal state machine to
perform the program and erase sequences. The embedded hardware algorithm uses an
internal oscillator to control the high voltage pulse duration and hardware control logic. The
embedded hardware algorithm is also responsible for performing all margin reads and
applying high voltage pulses to ensure each bit is programmed or erased with sufficient
margin. Upon successful program or erase operation, the program/erase hardware control
logic terminates the program or erase operation with a pass status (PEGOOD = 1). The
program/erase control logic will time out in the event that the maximum program or erase
time is exceeded and return a fail status (PEGOOD = 0).
21.3.7
Programming
To modify the charge stored in an isolated element of the UC3F bit from a logic 1 state to
a logic 0 state, a programming operation is required. This programming operation applies
the required voltages to change the charge state of the selected bits without changing the
logic state of any other bits in the UC3F array. The program operation cannot change the
logic 0 state to a logic 1 state; this transition must be done by the erase operation.
Programming uses a program data latch to store the data to be programmed and an address
latch to store the word address to be programmed. The UC3F Array may be programmed
by byte (8 bits), half-word (16 bits), or word (32 bits).
Blocks of the UC3F EEPROM that are protected (PROTECT[M] = 1, SBEN[N] = 1 and
SBPROTECT[N] = 1) will not be programmed. Also, if EPEE = 0, no programming
voltages will be applied to the array. If B0EPEE = 0, no programming voltages will be
applied to block 0 or small block 0 depending on the state of SBEN[0] and the configuration
of the array.
21.3.7.1 Program Sequence
The UC3F EEPROM module requires a sequence of writes to the high voltage control
register (UC3FCTL) and to the program data latch in order to enable the high voltage to the