What is the switching speed of a GPIO pin for STM32WB55?

[KKIM.6]

I want to use an external multiplexer to increase the number of ADC but switching speed is one of concern.

Fortunately, some multiplexer has a 13 ns switching speed (~100 MHz) and I'm planning to switch it using a GPIO signal.

However, it arises concerned on the switching speed of the GPIO pin also.

What is the switching speed of a GPIO pin for STM32WB55 microcontroller?

[waclawek.jan]

How do you plan to control that pin, exactly?

The ADC has a sampling phase and then a conversion phase. You can switch anytime during the conversion phase. Switching speed is surely not a concern at all.

Read the ADC chapter in RM.

JW

[KKIM.6]

Right now, I'm focusing on this issue.

I assembled the STM32WB55VG microcontroller and 8:1 mux.

The mux is contolled by three GPIO pin for [2:0] encoding to select channel.

The output of mux is connected to the ADC and I can see the ADC data using DMA.

If I select one channel in the mux, I can collect data exactly.

However, if I operate the mux with switching channel (I gave ~1 ms of interval for each channel), the most recent channel data is filled to the previous channel (last channel data only appears in all the channel data).

I know that the microcontroller has single ADC and multiple channel itself and it works very well when I use scan conversion mode. It imply that there is a very quick reset state in the ADC to restart measurement for next channel.

So, I wonder how can I force to reset ADC measurement in the coding.

Is it possible?

[AScha.3]

i know, it is hard work - but , if you would RTFM ,

you could read it yourself, on P. 137 : 1,7ns.