I am powering a 2x16 LCD with 5V but interfacing it to a processor powered by 3.3V. The pins on the processor are 5V tolerant so the D0-D7 lines are safe to interface the processor to the display.
My question is the Vih specification, on some data sheets (ex. NHD-0216PZ-FL-YBW) the Vih min. specification is 2.2V so driving it with 3.3V logic should be fine. On another (ex. NHD‐0216T2Z‐FSY‐YBW‐P) the Vih min specification is 0.7*Vdd = 3.5V so not OK. The data sheets for both reference either the SPLC780D driver (2.2Vih min) and ST7066U (0.7*Vdd).
Is there a way to know if a particular build has the SPLC780D driver chip? The main page for all of the 2x16 character LCDs state that the controller is the ST7066U for all of the modules, so I run the risk of bad operation with 3.3V logic?
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