1.8V VDD and 3.3V IO

[CPetr.2]

I am utilizing the STM32F767ZI in a design and am wondering if the following will cause any issues. I have VDD set to 1.8V so the standard IO is 1.8V, however, JTAG and USB-DFU control use 3.3V standard.

Based on the DS, the corresponding pins (PA11-14, PB3, NRST) are all FT meaning they are 5V tolerant. So, am I correct in assuming that I can use the 3.3V JTAG/USB-DFU without needing level shifters to bring them down to 1.8V?

[TDK]

> ... USB-DFU control use 3.3V standard.

USB has its own differential signal control. Not really equivalent to a "3.3V standard".

USB requires VDDUSB of at least 2.7V, per the datasheet. If you have VDDUSB = VDD = 1.8V, it won't work.

Not sure on JTAG.

[CPetr.2]

Ah you're right, I just tested the USB-DFU and it wasn't detected below 2.2V VDD so level shifters are the way to go. Thanks!