
Flash EEPROM 64K
MC9S12T64Revision 1.1.1
226
Flash EEPROM 64K
MOTOROLA
Program and
Erase Sequence in
Flash Super User
Mode
The Flash EEPROM module requires that the USER program/erase
operations be allowed via programming the address (FADDR) and data
(FDATA) registers. The operation is controlled via the FSUM bit in the
CALCFG register (refer to page
241
). Super user operation is indicated
when this bit is set.
When FSUM = 1, a register write to the address register will start the
monitor state machine for the operation. During this sequence the
address presented on the core data bus is monitored for protection
violation and operation sequence is monitored for access errors. The
access error is set if the strict sequence of, address register access
followed by the data register access is not observed. Address alignment
is also checked for access error indications. The operation sequence is
shown below:
1.
Write the address word to be programmed to the valid Flash
address space, shown in
Table 35
, to the FADDR register. The
address will be stored in internal buffers.
Write the data word to the FDATA register. The data will be stored
in internal buffers.
2.
NOTE:
For program, all address bits are valid. For erase, the value of the data
bytes is don’t care. For mass erase, the address can be anywhere in the
available address space of the block to be erased. For sector erase the
address bits[8:0] are ignored for the Flash.
3.
Write the program or erase command to the command buffer.
These commands are described in
FCMD — Flash Command
Register
and listed in
Table 45
in page
216
.
Clear the CBEIF flag by writing a “1” to it to launch the command.
When the CBEIF flag is cleared, the CCIF flag is cleared by
hardware indicating that the command was successfully
launched. The CBEIF flag will be set again indicating the address,
data and command buffers are ready for a new command
sequence to begin.
4.
A summary of the program algorithm is shown in
Figure 29
. For the
erase algorithm, the user writes either a mass or sector erase command
to the FCMD register.
F
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n
.