F746 proto has problems in reset

[LMI2]

I think programming was successful at first time but after that I get only write protection and reset errors.

STM32 ST-LINK Utility and STM32CubeProgrammer complain about reset and write protection. But reset pin voltage is now about 3.2V.

Cube programmer error messages:

23:46:46 : STM32CubeProgrammer API v2.3.0

23:46:56 : ST-LINK SN : 49FF6E066775545547520167

23:46:56 : ST-LINK FW : V2J35S0

23:46:56 : Voltage    : 2.91V

23:46:58 : Error: ST-LINK error (DEV_TARGET_NOT_HALTED)

23:47:24 : Read File: C:\MDK-ARM\ST_Arm746relekortti2\ST_Arm746relekortti2.hex

23:47:24 : Number of segments: 1

23:47:24 : segment[0]: address= 0x8000000, size= 0xDA0

23:47:45 : ST-LINK SN : 49FF6E066775545547520167

23:47:45 : ST-LINK FW : V2J35S0

23:47:45 : Voltage    : 2.91V

23:47:48 : Error: ST-LINK error (DEV_TARGET_NOT_HALTED)

23:48:06 : ST-LINK SN : 49FF6E066775545547520167

23:48:06 : ST-LINK FW : V2J35S0

23:48:06 : Voltage    : 2.91V

23:48:10 : Error: ST-LINK error (DEV_TARGET_HELD_UNDER_RESET)

[TDK]

What is a "F746 proto" board?

You can remove readout protection in STM32CubeProgrammer.

[LMI2 · Accepted solution]

I went through all CPU pins and the board started working.

[JRF.1]

How did you solve the problem? Could you help me, please?

Did you use the STM32CubeProgrammer to go through the CPU pins? I'm facing the same problem but only receiving the "(DEV_TARGET_HELD_UNDER_RESET)" message. All my protection checkboxes are unchecked in the CubeProgrammer. It only works in the ''hot plug'' mode, but can't download any code in my stm32f103 board.

[LMI2]

Last spring I had a lot of time in my hands, as a lot of others I think. So, I had plenty of time to debug or fight with the board. Lets see what I can remember.

Stlink V2 needs to be connected to USB. If it is not connected, it pulls reset down.

They say that reset pin of the CPU doesn't need a pull up resistor. When I was in real trouble, I needed that pull up resistor.

I use a 100pin STM32H750 which is pin to pin compatible 100pin STM74F746 CPU. At least the internal power supply of H750 has three settings. If you use high clock speed like 480MHz, only one, the highest, power setting works. Wrong setting, and and your CPU stops.

There are atleast two programming softwares for PC, STM32 ST-LINK Utility and Cube programmer. I tried them both, and sometimes the other worked and sometimes the other. When everything works, you can use programmer directly from IDE.

Of course you have to search this forum, sometimes there are answers, and sometimes not. And read every datasheet, application note and so on.

Check programming connector.

STM32 ST-LINK Utility has program under reset option.