MCU STM32F733ZE doesn't START

[SFELL.1]

Hello Community,

We have an issue on a design with an MCU STM32F733ZE on a custom electronic board, we don't manage to program it through STM32Cubre Programmer ("No STM32 found"). We observed that the power consumption is very low, less than 0.1mA so we assume that the MCU doesn't turn ON, we observed that the SWDIO pin is on 3.3V permanently and we couldn't drive to low level when connected to the ST-link programmer, and the level doesn't change even if we put the NRST pin to low level. On the design side, PDR pin was first floating, a resistor was not mounted, but now the resistor is mounted, the MCU behaviour doesn't change. So we wanted to know, what is the expected consumption when the MCU is powered up for the first time ? What happen if the PDR pin was floating when first power up ? The NRST pin level seems to no have any impact on the MCU, no consumption changing, no internal voltage reference change (We measure 1.1V on the internal voltage ref).

Best regards,

[Tesla DeLorean]

If the SWD connectivity doesn't work the connections are wrong, or the IC is dead in the water.

Make sure the analogue supplies are connected. Powers POR and PLL's

Make sure the part is orientated correctly.

Make sure the VCAP capacitors are in place, and you can measure ~1.25V on them.

You should have to do anything to NRST, if the part is functioning this pin should be at about VDD

[SFELL.1]

Thanks for the feedback, in fact, the MCU doesn't heat and doesn't draw current, so I assume that it's still working, the NRST pin is on 3.3V.

The SWDIO pins is held at 3.3V and SCLK strangely at 1V.

I've checked the orientation, it's correct.

HOw can I check PLL's and POR?

[Tesla DeLorean]

>> SCLK strangely at 1V.

Yeah, sorry I've got no visibility into your design or what you're doing.

Suggests you're not looking at the right pins.

The secondary signs-of-life method is to use the System Loader, pull BOOT0 high, and interact with it on one of of the assigned UARTs, say USART1 PA9/PA10, send an 0x7F data pattern at 9600 8E1 and see if it responds.

The POR should be reflected via NRST, I'm just saying the POR/PLL are in the analogue power domain, not just the ADC/DAC if you've determined you aren't using those.

[SFELL.1]

Thanks for your replay, in fact, i just managed to communicate with it through UART, putting BOOT0 to high Do you think, that we can work around the SWD connection problem and program all the other functions through UART ?

[Tesla DeLorean]

You should be able to program test code and validate other aspects of the design, using the USART as a means to ​report diagnostic or telemetry.

[Jaroslav BECKA]

Hi,

you may find the AN4661: Getting started with STM32F7 Series MCU hardware development useful.

How does the SWD signals connection look like?

Are there any pull-ups/pull-downs on SWDIO/SWCLK?

Can you share the electrical schematic (MCU part)?