ST92F124/F150/F250 - SINGLE VOLTAGE FLASH & E3 TM (EMULATED EEPROM)
REGISTER DESCRIPTION (Cont’d)
When in Erase Suspend the memory accepts only
the following operations: Read, Erase Resume
and Byte Program. Updating the E3 TM memory is
not possible during a Flash Erase Suspend.
0: Resume sector erase when FWMS is set again.
1: Suspend Sector erase
E
3 TM CONTROL REGISTER (ECR)
Address: 224001h /221001h- Read/Write
Reset value: 000x x000 (xxh)
7
6
5
4
3
2
1
0
EWMS EPAGE ECHIP
WFIS FEIEN EBUSY
Bit 1 = PROT: Set Protection (Read/Write).
This bit must be set to select the Set Protection op-
eration. This bit is automatically reset at the end of
the Set Protection operation.
The E3 TM Control Register is used to enable all the
operations for the E3 TM memory.
The ECR also contains two bits (WFIS and FEIEN)
that are related to both Flash and E3 TM memories.
The Set Protection operation allows “0”s in place
of “1”s to be programmed in the four Non Volatile
Protection registers. From 1 to 4 bytes can be en-
tered (in any order, no need for an ordered ad-
dress sequence) before starting the execution by
setting the FWMS bit. Data to be programmed and
addresses in which to program must be provided
(through an LD instruction, for example). Protec-
tion contained in addresses that are not entered
are left unchanged.
Bit 7 = EWMS: E3 TM Write Mode Start.
This bit must be set to start every write/erase oper-
ation in the E3 TM memory. At the end of the write/
erase operation this bit is automatically reset. Re-
setting by software this bit does not stop the cur-
rent write operation.
0: No effect
1: Start E3 TM write
0: Deselect protection
1: Select protection
Bit 6 = EPAGE: E3 TM page update.
This bit must be set to select the Page Update op-
eration in E3 TM memory. The Page Update opera-
tion allows to write a new content: both “0”s in
place of “1”s and “1”s in place of “0”s. From 1 to 16
bytes can be entered (in any order, no need for an
ordered address sequence) before starting the ex-
ecution by setting bit EWMS. All the addresses
must belong to the same page (only the 4 LSBs of
address can change). Data to be programmed and
addresses in which to program must be provided
(through an LD instruction, for example). Data
contained in page addresses that are not entered
are left unchanged. This bit is automatically reset
at the end of the Page Update operation.
Bit 0 = FBUSY: Flash Busy (Read Only).
This bit is automatically set during Page Program,
Byte Program, Sector Erase or Set Protection op-
erations when the first address to be modified is
latched in Flash memory, or during Chip Erase op-
eration when bit FWMS is set. When this bit is set
every read access to the Flash memory will output
invalid data (FFh equivalent to a NOP instruction),
while every write access to the Flash memory will
be ignored. At the end of the write operations or
during a Sector Erase Suspend this bit is automat-
ically reset and the memory returns to read mode.
After an Erase Resume this bit is automatically set
again. The FBUSY bit remains high for a maxi-
mum of 10µs after Power-Up and when exiting
Power-Down mode, meaning that the Flash mem-
ory is not yet ready to be accessed.
0: Deselect page update
1: Select page update
Bit 5 = ECHIP: E3 TM chip erase.
This bit must be set to select the Chip Erase oper-
ation in the E3 TM memory. The Chip Erase opera-
tion allows to erase all the E3 TM locations to FFh.
The execution starts by setting bit EWMS. This bit
is automatically reset at the end of the Chip Erase
operation.
0: Flash not busy
1: Flash busy
0: Deselect chip erase
1: Select chip erase
Bit 4:3 = Reserved.
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