Program/Erase Parallelism; Erase; Table 8. Program/Erase Parallelism - ST STM32F40 Series Reference Manual

RM0090
3.5.2

Program/erase parallelism

The Parallelism size is configured through the PSIZE field in the FLASH_CR register. It
represents the number of bytes to be programmed each time a write operation occurs to the
Flash memory. PSIZE is limited by the supply voltage and by whether the external V
supply is used or not. It must therefore be correctly configured in the FLASH_CR register
before any programming/erasing operation.
A Flash memory erase operation can only be performed by sector, or for the whole Flash
memory (mass erase). The erase time depends on PSIZE programmed value. For more
details on the erase time, refer to the electrical characteristics section of the device
datasheet.
Table 8 provides the correct PSIZE values.
Table 8. Program/erase parallelism
Voltage range 2.7 - 3.6 V
with External V
Parallelism size
PSIZE(1:0)
Note: Any program or erase operation started with inconsistent program parallelism/voltage range
settings may lead to unpredicted results. Even if a subsequent read operation indicates that
the logical value was effectively written to the memory, this value may not be retained.
To use V
pad. The external supply must be able to sustain this voltage range even if the DC
consumption exceeds 10 mA. It is advised to limit the use of VPP to initial programming on
the factory line. The V
Flash memory might be damaged.
3.5.3

Erase

The Flash memory erase operation can be performed at sector level or on the whole Flash
memory (Mass Erase). Mass Erase does not affect the OTP sector or the configuration
sector.
Sector Erase
To erase a sector, follow the procedure below:
1. Check that no Flash memory operation is ongoing by checking the BSY bit in the
FLASH_SR register
2. Set the SER bit and select the sector out of the 12 sectors (for STM32F405xx/07xx and
STM32F415xx/17xx) and out of 24 (for STM32F42xxx and STM32F43xxx) in the main
memory block) you wish to erase (SNB) in the FLASH_CR register
3. Set the STRT bit in the FLASH_CR register
4. Wait for the BSY bit to be cleared
Voltage range
PP
x64
11
, an external high-voltage supply (between 8 and 9 V) must be applied to the V
PP
supply must not be applied for more than an hour, otherwise the
PP
Doc ID 018909 Rev 4
Voltage range
2.7 - 3.6 V 2.4 - 2.7 V
x32
10
Embedded Flash memory interface
Voltage range
2.1 - 2.4 V
x16
01
PP
Voltage range
1.8 V - 2.1 V
x8
00
PP
66/1422