Hello, I have some problems programming a custom STM32F417 board.

[SArzb.1]

The Flash of the chip can't be programmed. Mostly the error is that writing the first byte failed. But sometimes it is able to write a few bytes. It even worked like 3 times. The behavior is consistent over STM32CubeProgrammer and ST-Link Utility, and JTAG and SWD.

There are some side effects:

• STM32CubeProgrammer does not report the Flash size correctly. It reports 1M instead of 515K, ST-Link Utility reports correctly
• Erasing the Flash does not always work
• Sometimes the flash changes its content. Mostly switching between 2 or 3 values

Thank you for your help.

[Tesla DeLorean · Accepted solution]

Do a through review of your design, perhaps with an ST FAE assigned to your account.

With good design, the JTAG/SWD should be quite robust.

Differences on a board level check for power and component issues.

For FLASH, the VCAP pins and capacitors being particularly important.

Don't float BOOT0

Have NRST connected to any debug headers.

Make sure VDDA and VDD are powered. Similarly digital/analogue grounds.

[KnarfB]

Lower the SWD clock frequency in the tools used.

hth

KnarfB

[SArzb.1]

@Community member​ thank you very much. VDDA was not connected.

Its working now.

@KnarfB​ Thank you for your help.