Subject: STM32H753ZI cannot control PC02 as GPIO or SPI2_MISO functionality.

[QuocBui]

Hi expert, our project is currently in the development stage. We are using the NUCLEO-H753ZI Development Kit for firmware development while awaiting the arrival of our custom board from the manufacturer. The dev-kit employs the STM32H753ZI (LQFP144), which has a slightly different pin configuration compared to the MCU on our custom board STM32H753ZI (LQFP100).

During our development process, we encountered an issue with using PC2_C to control SPI2 (SPI2_MISO), where it consistently pulls low. Despite extensive debugging efforts, including configuring the pin as GPIO and measuring with a logic analyzer, the issue persisted. Upon researching similar cases on the ST Community forum STM32H735V (LQFP100) PC2_C and PC3_C speed and FAQ: Default State of STM32H7 switches connecting Pxy_C and Pxy pads, we realized it might be related to a known issue in the STM32H7 family, specifically a bug in the silicon regarding the PC02 pin.

After reviewing the documentation and conducting tests on our end, we observed that while PC3_C can be controlled as expected, PC2_C cannot be controlled even when manipulating the external pad switches using the provided code:

HAL_SYSCFG_AnalogSwitchConfig(SYSCFG_SWITCH_PC2, SYSCFG_SWITCH_PC2_CLOSE);
HAL_SYSCFG_AnalogSwitchConfig(SYSCFG_SWITCH_PC3, SYSCFG_SWITCH_PC3_CLOSE);

1. We would appreciate confirmation regarding whether this issue is indeed related to the chip itself.
2. Additionally, our custom board utilizes the STM32H753ZI (LQFP100) package, which differs slightly from the package used in the NUCLEO-H753ZI. We would like to know if this package also experiences the same issue.

Thank you in advance for your assistance.

[QuocBui]

Hi @SofLit , I have just tested the code that you provided on the NUCLEO-H743ZI Dev-Kit on PC2_C Pin, and it worked as expected (toggled as I anticipated).

However, for the NUCLEO-H753ZI, it does not work; similar to the issue I reported to you. 

[SofLit]

There is an issue with that chip and the IO is defective. You need to replace the chip. As I said H743 and H753 are the same die so it’s not a silicon issue.

[QuocBui]

Hi @SofLit , I tried two NUCLEO-H753ZI Dev-Kits, and the issue persists. Do you think there might be a problem with the IO during the manufacturing of the Dev-Kit?

[SofLit]

That's strange. 

I will try to find NUCLEO-H753ZI board as I don't have one and get back to you as soon as possible (this week).

Hope I will find a board.

[SofLit]

Hello,

I'm getting back to you regarding this subject.

I got a NUCLEO-H753ZI board and did a test and didn't face any issue with PC2_C.

Could you please tell which board reference do you have for both NUCLEO-H753ZI and NUCLEO-H743ZI?

I have MB1364E for both boards. So what do you have for both boards?

[Andreas Bolsch]

Could you please check register contents at 0x580244F4, 0x58024554 and 0x58000404 *after* the calls of 

HAL_SYSCFG_AnalogSwitchConfig(...);

[QuocBui]

Hi @Andreas Bolsch  Okay, I will check these values and give you the feedback on this.

[QuocBui]

Hi @SofLit 

1. We have both boards: MB1364E (NUCLEO-H753ZI and NUCLEO-H743ZI). On the NUCLEO-H743ZI board, we get the P2C_C, but the NUCLEO-H753ZI does not work.
2. We are using the NUCLEO-H753ZI board for firmware development (It utilizes the STM32H753ZITX, which is used for development purposes. However, we actually use the STM32H753VIT6TR chip for our custom board that is coming in a few days).

[SofLit]

Hello,

Question:

On which connector are you probing PC2_C pin? CN9 or CN11?

If on PC9, what about the SB53 solder bridge? is it soldered?

Could be better to check the continuity between the MCU pin (pin 28) and the connector pin to be sure the HW doesn't present an issue.

[QuocBui]

Hi @SofLit , I attached a probe to CN11 (PC2), soldered the header, and measured the signal there.