PSD834F2A-70UI View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
PSD834F2A-70UI Datasheet PDF : 128 Pages
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Erasing Flash memory
9
Erasing Flash memory
PSD8XXFX
9.1
Flash Bulk Erase
The Flash Bulk Erase instruction uses six WRITE operations followed by a READ operation
of the status register, as described in Table 10. If any byte of the Bulk Erase instruction is
wrong, the Bulk Erase instruction aborts and the device is reset to the Read Flash memory
status.
During a Bulk Erase, the memory status may be checked by reading the Error flag bit (DQ5),
the Toggle flag bit (DQ6), and the Data Polling flag bit (DQ7), as detailed in Section 8:
Programming Flash memory. The Error flag bit (DQ5) returns a '1' if there has been an
Erase Failure (maximum number of Erase cycles have been executed).
t(s) It is not necessary to program the memory with 00h because the PSD automatically does
this before erasing to 0FFh.
uc During execution of the Bulk Erase instruction, the Flash memory does not accept any
d instructions.
te Pro 9.2
Flash Sector Erase
le The Sector Erase instruction uses six WRITE operations, as described in Table 10.
so Additional Flash Sector Erase codes and Flash memory sector addresses can be written
b subsequently to erase other Flash memory sectors in parallel, without further coded cycles,
O if the additional bytes are transmitted in a shorter time than the timeout period of about
- 100µs. The input of a new Sector Erase code restarts the timeout period.
t(s) The status of the internal timer can be monitored through the level of the Erase timeout flag
bit (DQ3). If the Erase timeout flag bit (DQ3) is ’0,’ the Sector Erase instruction has been
c received and the timeout period is counting. If the Erase timeout flag bit (DQ3) is '1,' the
u timeout period has expired and the PSD is busy erasing the Flash memory sector(s). Before
rod and during Erase timeout, any instruction other than Suspend Sector Erase and Resume
Sector Erase instructions abort the cycle that is currently in progress, and reset the device
P to READ mode. It is not necessary to program the Flash memory sector with 00h as the
tePSD does this automatically before erasing (byte = FFh).
leDuring a Sector Erase, the memory status may be checked by reading the Error flag bit
so (DQ5), the Toggle flag bit (DQ6), and the Data Polling flag bit (DQ7), as detailed in
Ob Section 8: Programming Flash memory.
During execution of the Erase cycle, the Flash memory accepts only Reset and Suspend
Sector Erase instructions. Erasure of one Flash memory sector may be suspended, in order
to read data from another Flash memory sector, and then resumed.
9.3
Suspend Sector Erase
When a Sector Erase cycle is in progress, the Suspend Sector Erase instruction can be
used to suspend the cycle by writing 0B0h to any address when an appropriate Sector
Select (FS0-FS7 or CSBOOT0-CSBOOT3) is high. (See Table 10). This allows reading of
data from another Flash memory sector after the Erase cycle has been suspended.
Suspend Sector Erase is accepted only during an Erase cycle and defaults to READ mode.
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Doc ID 7833 Rev 7
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