Questions about STM32F042T6Y

[Fabrizio70]

Hello i  two questions ,

1) i use mcu STM32F042T6Y a give the same power  supply 3.3v to pin VDD,VDDA and VDDIO2, is this a problem?(many gpio(i chose the gipo tollerant) input  of mcu work to 5V and i use the usb host of mcu )

2) i want use  a external oscillator ASE-8000MHzLCT i connected the oscillator output to PFO and PF1 is flating (not connect),is this corret ? if yes , the oscillator   external give me  greater stability of interal rc clock ? (i sue mcu as usb host virtual com port)

[Foued_KH · Accepted solution]

Hello @Fabrizio70 , 

1) 

You should also respect the the maximum allowed injected current values.

Foued

[Fabrizio70]

I have VD VDDA Vddio2 are same voltage so i  think that have respect table 18.

For input voltage i have 5v on the gpio FT so if i understand the maxim volge on FT  pin is  VDDIO2+4=3,3+4=7 V (I DONT HAVE INTERNALL pull-up/pull-down)

For the the maximum allowed injected current values i dont understand the table 19 my conditon is this :

VIN =5  VDDIO2 =3,3 V so i have VIN > VDIDDO2 (  positive injection)

the table 19 if i understand give me a current positive injextion 0 mA , seem that dont have problem VIN =5V , it is right or i must use voltage traslator ?

thank yuo