Teensy 3.2: Can it drive TTL?

[ieure]

I see that the Teensy 3.2 is "5v tolerant," but it's not entirely clear to me if its GPIO can also drive a TTL device, or whether I'd need a level converter for that.

 

[Frank B]

The GPIO-Output-Voltage is 3.3V.

A TTL input signal is defined as "low" when between 0 V and 0.8 V with respect to the ground terminal, and "high" when between 2 V and VCC (5 V)

But there are different TTL-Families. Even 3.3V TTL exists.

https://en.wikipedia.org/wiki/Logic_family

 

[tni]

You have to look at the datasheet. Things using real TTL logic levels are fine. CMOS stuff running at 5V Vcc often requires 0.65-0.7 Vcc for a logic high, which is an issue.

E.g. 74HCT works fine, 74HC is problematic.