STM32L451RCT6 failed to bootloader command Extended Erase Memory, while -RET6 does.

[JKim.25]

Hi,

I'm working on my STM32 project, having DFU mode on machine. (using UART bootloader)

I just have failed to DFU my STM32L451RCT6, but with same logic, -RET6 has succeeded!

When I send EER(Extended Erase) command (0x44, 0xBB) to RCT6, It send me ACK at first.

Right after it, I send mass erase address and checksum (0xFF, 0xFF, 0x00) to it, but it sent me NACK back!

I also checked bootloader version, and the version 3.1 provides EER function.

Why is there such a difference?

In datasheet, RET6 is just having twice as much flash as RCT6.

I also added write unprotected and readout unprotected before Extended Erase, but it didn't work.

Changing UART baudrate from 115200 to 57600 also didn't work.

Can anybody help me?

[Bubbles]

Hi @JKim.25​,

you sort of got the correct answer in your question. The difference is the memory size indeed. Product is the same BL version, but different feature set, limited by memory size.

It's described in AN2606 chapter 4.4 - some products just don't get to have mass erase. It's not essential.

Rgds,

Jarda