PA4 not fully pulling down on STM32U5G9ZJT6Q
Hi, good morning.
I’ve an application based on STM32U5G9ZJT6Q; I’ve deployed a board, based on that chip, in order to control and manage user functions for an audio Hi-fi preamplifier.
Among the interfaces which were configured, I’ve SPI1, connected to a volume control chip. NSS configured in software. Latch is coming from a GPIO (PA4).
Well, regardless the configuration of this pin I’m adopting, I cannot have this latch signal pulling down to 0. it settles at 2.2 Volt (when the pin is ‘reset’), this is the minimum level, from the nominal 3.15 Volt. This does not make my audio chip work, as this 2.2 level still gets interpreted as ‘high’. I measured those levels directly at the output of PA4, no other components connected.
Which is the root cause of this ? I mean, do you think it’s hardware failure on this GPIO only, or some conflict ?
I managed to get it working by utilizing another GPIO, but I’m keen to know the reason why.
For your information, here the other interfaces (all of them are working ok):
- SPI1, as said
- SPI2
- SPI3
- I2C1
- I2C2
- I2C3
- LTDC, display. 24 bits RGB
- About 10 interrupts configured on input GPIOs
Thank you very much in advance for your help !
Matteo