Confused about F413 flash programming and bootloader

[Dave Nadler]

We're looking at using the F413 for a slave in a many MCU product, and using its SPI bootloader so master can reprogram an array of slaves over SPI. I'm confused about the bootloader and flash programming, in particular:

(1) Is high voltage VPP and high current on BOOT0 pin required for any flash programming? Or only advantageous in some circumstance? Or can I just use 3.3v?

(2) datasheet says "parts are delivered with flash erased". So where is the bootloader? Do I need to avoid erasing the entire flash to preserve the bootloader? Or is it in ROM somewhere and mapped in only when BOOT0=1? Or is that Boot1=VPP?

Thanks in advance for any clarification!

Best Regards, Dave

[Tesla DeLorean]

The high VPP speeds programming/erase as the charge-pump doesn't need to generate the higher voltages internally.

The System Loader is in some OTP/ROM region, nominally in the 0x1FFxxxxx space. You aren't provided with means or opportunity to erase or modify it. The erase only relates to the user flash in the 0x080xxxxx space

[Dave Nadler]

Thanks @Community member​ ! If I just use Vpp=3.3v to signal bootloader, do I need to provide high-current capability into BOOT0? or just any-old logic output will do?

[Tesla DeLorean]

It doesn't need VPP to work, pull-up BOOT0, or drive it high, to enter the System Loader, it will derive the power it needs from VDD.

The VPP option is to allow production test fixturing to more rapidly program the device. And why it should only be provided for a finite period.

[Dave Nadler]

So no high-current required. Thanks @Community member​ !