2018-11-11 06:36 PM
I understand that VDD needs to be 3V3 if using the internal full speed transceiver, since STM32H750VBT6 has no VDDUSB input, but if I am using an external high speed USB ULPI PHY can the mcu be run at 1V8 and still use USB? I wan't quite able to figure out from the datasheet.
Thanks,
Jacob
2018-11-11 07:37 PM
Q u i c k y guess ...... Yes.
approx 1.2-1.5V is the normal switching point so 1.8 is high...
which ULPI unit ?
2018-11-11 07:51 PM
A TUSB1210BRHBR, http://www.ti.com/lit/ds/symlink/tusb1210.pdf
2018-11-11 08:12 PM
on the ULPI,
Put VDDIO at 1.8V , and Vdd18
REF Clk at gnd, for an external clock input
on H7
VDD at 1.8V
2018-11-11 08:13 PM
Ok Thanks!
2018-11-11 08:16 PM
You will need low ESR Cap and extra caps..
you have no room to spike downwards, you need 10x capacity..( 0.1, 0.01, 1u 2.2u all caps)
You may need a 4layer board for the current spikes.