STM32H747-DISCO Core-Lock Problem

[CKILI.2]

Hello,

I’m using the STM32H747. When I set the RCC power source to RCC → Power parameters → Supply source = LDO, the core locks up; if I select SMPS, there’s no issue.

When I set CM7 to its maximum clock frequency (480 MHz) and CM4 to 240 MHz, the tool forces LDO and I can’t choose SMPS. In fact, for any CPU clock higher than 400 MHz, LDO becomes mandatory.

When I run the MCU with LDO, I can’t operate at the maximum clock frequency. If the core locks up, I set BOOT=1 via R192 and perform a Full Chip Erase. After that, if I still keep LDO selected, I can connect once and program the device, but on the second programming attempt—or after unplugging and replugging the board—I get a “No target” error again. I see the same problem even at lower clock frequencies when LDO is selected.

Previously, when I programmed the MCU at the maximum clock frequency, I did not encounter this issue. The code that used to run without problems at that time is now producing the same error today.

Also, I’m attaching an image showing my boot address settings—could you please check if they look correct?Finally, only when I select the board and create a project in CubeIDE (not in CubeMX), I receive the attached warning at the beginning.

Do you have any ideas on how to resolve this?

Thank you.

[mƎALLEm · Accepted solution]

Hello,

I don't see why you need to switch from LDO to SMPS with STM32H747-DISCO board. That board is configured in SMPS by hardware by default (unless you modified the hardware) and you can't set the power supply to LDO this will lock up the MCU. 

LDO or SMPS depends on your hardware. The power configuration in your software depends strongly on what is set in your board: LDO or SMPS.

Also SMPS mode is not available in the VOS0 voltage scale. From the datasheet:

So SMPS is available with VOS1 (maximum 400MHz).

To unlock your MCU, please read this article: How can I recover my STM32H7/STM32H7RS board after facing a power configuration deadlock?

[CKILI.2]

Hello,

At 480 mhz it only works with LDO, as a result it locks up when I select LDO at maximum or any frequency.

[mƎALLEm]

Again you can't use LDO mode with that board. It's configured in SMPS by hardware unless you modified it to support the LDO mode.