Will 5V Tolerantdigital pins drive a LCD Display?

Status
Not open for further replies.
W

WildBill57

Member
Using a T-LC (switched from a different processor) in a project. Until I get the 3.3V OLED display to work, I have several LCD displays that need 5V to work. I'm using a 3.3V:5V level shifter board and would love to eliminate it. Will the 3.x drive these ok?

Thanks.
 
No, the 5v tolerance only applies to the pin being able READ 5v with digitalRead and not cause damage. The output from digitalWrite is always 3.3v. If the pin can be used with analogRead, any voltage between 3.3v and 5v registers as 3.3v.

Note, in terms of the 3.x, the 3.0 and 3.6 are not 5v tolerant (just like the LC is not 5v tolerant). The 3.1, 3.2, and 3.5 are 5v tolerant.

In terms of being able to drive the displays, it is up to the display. If the display can read 3.3v as being high and it is a SPI display, you might be able power the display with VIN and use 3.3v for MOSI/SCLK pins. However, for a lot of devices the rule of thumb appears to be that voltage over 0.7x is read as high, and for VIN = 5v, that would be 3.5v. So, it might be iffy, unless the display is designed to accept 3.3v logic.
 
Last edited:
With displays I've had fairly good luck running them off 3.3V logic, but yes the rule is 0.7=>3.5V so wouldn't base any production designs but should be fine to try. Do watch for anything that tries to drive logic back, basic restive divisor can fix that.
 
Status
Not open for further replies.
Back
Top