
Prelimnary
PSD813F Famly
27
The
PSD813F
Functional
Blocks
(cont.)
9.1.1.8 Erasing Flash Memory
9.1.1.8.1. Flash Bulk Erase Instruction
The Flash Bulk Erase instruction uses six write operations followed by a Read operation of
the status register, as described in Table 9. 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 status bits DQ5, DQ6,
and DQ7, as detailed in section 9.1.1.7. The Error bit (DQ5) returns a ‘1’ if there has been
an Erase Failure (maximum number of erase cycles have been executed).
It is not necessary to program the array with 00h because the PSD813F will automatically
do this before erasing to 0FFh.
During execution of the Bulk Erase instruction, the Flash memory will not accept any
instructions.
9.1.1.8.2 Flash Sector Erase Instruction
The Sector Erase instruction uses six write operations, as described in Table 9. Additional
Flash Sector Erase 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 PSD813F is busy erasing 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 Array mode. It is not
necessary to program the Flash sector with 00h as the PSD813F1 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 9.1.1.7.
During execution of the erase instruction, the Flash block logic accepts only Reset and
Erase Suspend instructions. Erasure of one Flash sector may be suspended, in order to
read data from another Flash sector, and then resumed.