PSD813F1A-12J STMICROELECTRONICS [STMicroelectronics], PSD813F1A-12J Datasheet - Page 29

• Manufacturer Part Number: PSD813F1A-12J
• Description: Flash In-System Programmable (ISP) Peripherals for 8-bit MCUs, 5V
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ERASING FLASH MEMORY
Flash Bulk Erase
The Flash Bulk Erase instruction uses six write op-
erations followed by a Read operation of the status
register, as described in
byte of the Bulk Erase instruction is wrong, the
Bulk Erase instruction aborts and the device is re-
set to the Read Flash memory status.
During a Bulk Erase, the memory status may be
checked by reading status bits DQ5, DQ6, and
DQ7, as detailed in section entitled
MING FLASH MEMORY, page
(DQ5) returns a ‘1’ if there has been an Erase Fail-
ure (maximum number of erase cycles have been
executed).
It is not necessary to program the array with 00h
because the PSD will automatically do this before
erasing to 0FFh.
During execution of the Bulk Erase instruction, the
Flash memory will not accept any instructions.
Flash Sector Erase. The Sector Erase instruc-
tion uses six write operations, as described in
ble 8., page
confirm commands and Flash sector addresses
can be written subsequently to erase other Flash
sectors in parallel, without further coded cycles, if
the additional instruction is transmitted in a shorter
time than the timeout period of about 100 µs. The
input of a new Sector Erase instruction will restart
the time-out period.
The status of the internal timer can be monitored
through the level of DQ3 (Erase time-out bit). If
DQ3 is ‘0’, the Sector Erase instruction has been
received and the timeout is counting. If DQ3 is ‘1’,
the timeout has expired and the PSD is busy eras-
ing the Flash sector(s). Before and during Erase
timeout, any instruction other than Erase suspend
and Erase Resume will abort the instruction and
reset the device to READ mode. It is not neces-
sary to program the Flash sector with 00h as the
PSD will do this automatically before erasing
(byte=FFh).
During a Sector Erase, the memory status may be
checked by reading status bits DQ5, DQ6, and
DQ7, as detailed in section entitled
MING FLASH MEMORY, page
During execution of the erase instruction, the
Flash block logic accepts only Reset and Erase
20. Additional Flash Sector Erase
Table 8., page
27.
27. The Error bit
PROGRAM-
PROGRAM-
20. If any
Ta-
Suspend instructions. Erasure of one Flash sector
may be suspended, in order to read data from an-
other Flash sector, and then resumed.
Flash Erase Suspend
When a Flash Sector Erase operation is in
progress, the Erase Suspend instruction will sus-
pend the operation by writing 0B0h to any address
when an appropriate Chip Select (FSi) is true.
(See
data from another Flash sector after the Erase op-
eration has been suspended. Erase suspend is
accepted only during the Flash Sector Erase in-
struction execution and defaults to READ mode.
An Erase Suspend instruction executed during an
Erase timeout will, in addition to suspending the
erase, terminate the time out.
The Toggle Bit DQ6 stops toggling when the PSD
internal logic is suspended. The toggle Bit status
must be monitored at an address within the Flash
sector being erased. The Toggle Bit will stop tog-
gling between 0.1 µs and 15 µs after the Erase
Suspend instruction has been executed. The PSD
will then automatically be set to Read Flash Block
Memory Array mode.
If an Erase Suspend instruction was executed, the
following rules apply:
Flash Erase Resume
If an Erase Suspend instruction was previously ex-
ecuted, the erase operation may be resumed by
this instruction. The Erase Resume instruction
consists of writing 030h to any address while an
appropriate Chip Select (FSi) is true. (See
8., page
Attempting to read from a Flash sector that
was being erased will output invalid data.
Reading from a Flash sector that was not
being erased is valid.
The Flash memory cannot be programmed,
and will only respond to Erase Resume and
Reset instructions (READ is an operation and
is OK).
If a Reset instruction is received, data in the
Flash sector that was being erased will be
invalid.
Table 8., page
20.)
20). This allows reading of
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