Ясно. Про "Depending on I/O speeds and setup constraints" пишут следующее: 41.4.4 I/Os
Criteria used to define the maximum frequency of the I/Os:
• output duty cycle (40%-60%)
• minimum output swing: 100 mV to VDDIO - 100 mV
• Addition of rising and falling time inferior to 75% of the period
FreqMax VDDIOP0 powered Pins frequency 3.3V domain (1) 83.3 MHz
3.3V domain (1) 83.3 MHz
FreqMax VDDIOP1 powered Pins frequency 2.5V domain (2) 71.4 MHz
1.8V domain (3) 50 MHz