Voltage of Output Pins

Is anybody familiar with the voltage of the output pins? I looked through the technical reference sheet, but I could not find this information.

Thank you!

https://github.com/beagleboard/beaglebone-black/wiki/System-Reference-Manual#beaglebone-black-features-and-specification
"""
Expansion Connectors
  
Power 5V, 3.3V , VDD_ADC(1.8V)
3.3V I/O on all signals
McASP0, SPI1, I2C, GPIO(69 max), LCD, GPMC, MMC1, MMC2, 7
AIN (1.8V MAX), 4 Timers, 4 Serial Ports, CAN0,
EHRPWM(0,2),XDMA Interrupt, Power button, Expansion Board ID (Up to 4 can
be stacked)
"""

  The chipset used for the various beagles is 3.3V based (analog inputs
are limited to 1.8V). Presuming the old 30/70% thresholds for CMOS signals,
LOW is 0.0..1.0, HIGH is 2.3..3.3, 1.0..2.3 is indeterminate (the chips
should be outputting close to the 0.0 and 3.3 levels, but any input device
should accept the range).

Thank you so much