Flash memory interface

PM0059

12/29

DocID15687 Rev 5

2.5.2

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

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 sectors, bank 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.

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.

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

Flash memory might be damaged.

2.5.3

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 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

Table 4. Program/erase parallelism

Voltage range

2.7 - 3.6 V

with External

Voltage range

2.7 - 3.6 V

Voltage range

2.4 - 2.7 V

Voltage range

2.1 - 2.4 V

Voltage range

1. If IRROFF is set to VDD on STM32F20xx devices, this value can be lowered to 1.65 V when the device

operates in a reduced temperature range.

Parallelism

size

x64

x32

x16

x8

PSIZE(1:0)

11

10

01

00