I/O port configuration during/just after reset

[FYUJI.1]

Hi,

​

We started design with STM32G070RB for our new application.

And, i'd like to know the detail about below explanation about I/O port configuration during/just after reset at page.161 of the reference manual(RM0454).

|​During and just after reset, the alternate functions are not active and

|most of the I/O ports are configured in analog mode

Please help to answer below questions.

1. please teach the detail function of analog mode. Does this mode mean ADC function?
2. if analog mode means ADC function, device detect voltage on their pins during this mode?
3. During/after reset, every port have Pull-up, or Pull-down resistor?

Best regards,

yuji

[waclawek.jan]

The reset state of pins is given by the reset value of the GPIO registers, look at the description of these registers in RM.

"Analog mode" mainly means, that the digital input is disconnected, the pin is floating and is not influenced by the digital input's schmitt trigger's leakage. Analog functions like ADC might be connected electrically, but they are inactive (ADC is connected to pin only during sampling, anyway).

For pullup/pulldowns, again, refer to the reset value of GPIOx_PUPDR registers; most pins are fully floating with no pullup/pulldown (maybe except those participating in JTAG/SWD).

If you activate the built-in bootloader, after reset, there may be additional and not-very-well documented pullups/pulldowns used.

JW

[FYUJI.1]

Hi, JW

Thanks for your answer.

I understood well.

Best regards,

Yuji