I see in this topic...
that USB1 can't be forced to device in full speed mode, but there is in user manual (UM11126), Table 834. USB1 device command/status register (DEVCMDSTAT) bit 21 (R/W):
0: Default - drive K chirp during reset, go through HS negotiation.
1: Force the device to FS, do not drive K chirp during reset.
If USB1 device can be forced to full speed, in this case USB1 controller supporting crystal-less operation like USB0 or not? With both USB0 and USB1 active as full speed device.
Yes, you are right. USB1 can be used as Full speed. Forced FS value was updated in REV 2.4, 2021,OCT 07
The thread you referred was posted in 2020. Please don't use it.