UM2179 datasheet(43/48 Pages) STMICROELECTRONICS

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UM2179 Rev 9

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UM2179

Hardware layout and configuration

5.17.2

Bootloader identification

The bootloader version is identified by reading the bootloader ID at address 0x1FFF 6FFE:

•

the bootloader ID is 0x91 for bootloader version V9.1.

•

the bootloader ID is 0x92 for bootloader version V9.2.

5.17.3

Bootloader limitation

The limitation existing in bootloader V9.1 causes user Flash memory data to get randomly

corrupted when written via the bootloader SPI interface.

As a result, during bootloader SPI Write Flash operation, some random 64-bits (2 double-

words) may be left blank at 0xFF.

5.17.4

Affected parts

The STM32L496ZGT6, STM32L496ZGT6P, and STM32L4R5ZIT6 parts respectively

soldered on the NUCLEO-L496ZG, NUCLEO-L496ZG-P, and NUCLEO-L4R5ZI main

boards are marked with a date code corresponding to their manufacturing dates.

The STM32L496ZGT6, STM32L496ZGT6P, and STM32L4R5ZIT6 parts with a date code

prior or equal to week 37 of 2017 are fitted with bootloader V9.1. They are affected by the

limitation described in Section 5.17.3 and require one of the workarounds proposed in

Section 5.17.5.

The parts with a date code equal to week 38 of 2017 or later contain bootloader V9.2. They

are not affected by the limitation.

The STM32L4P5ZGT6 soldered on the NUCLEO-L4P5ZG main board is fitted with

bootloader V9.0.

To locate the visual date code information on the STM32L496ZGT6, STM32L496ZGT6P, or

STM32L4R5ZIT6 package, refer to the Package Information section in the data sheet

available at www.st.com. The date code related portion of the package marking is in the

Y WW format, where Y is the last digit of the year and WW is the week number. For

example, a part manufactured in week 38 of 2017 bears the 7 38 date code.

5.17.5

Workarounds

Three workarounds are proposed to overcome the limitation existing with bootloader V9.1.

Workaround 1

Add a delay between sending a Write command and its ACK request. The delay duration

must be the duration of the 256-byte Flash-write time.

Workaround 2

Read back after each write operation (256 bytes or end of user code flashing) and, in case

of error, perform the write operation again.

Workaround 3

Using the bootloader, load a patch code in RAM to write in Flash memory through the same

Write Memory write protocol as the bootloader This patch is provided by

STMicroelectronics. The patch code is available for download from the www.st.com website

with a readme.txt file containing the instructions of use.

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