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3.3 V vs. PCF8814-based "Nokia 1100" LCD?


Ivan Shmakov

Jan 1, 1970
I've got a "Nokia 1100" LCD, which (unless I be mistaken) is
based on PCF8814, whose digital I/O range is (1.7 .. 3.3) V.

The question is: is there an easy and safe way to connect it to
an otherwise 3.3 V (+/- some) circuit (as in: one interfacing an
SD card, or having an Arduino as its core, etc.)?

(Will a few diodes suffice, for instance?)

Also, the pinout for the LCD (e. g., [1]) has two pins for the
"+" rail (and one more for the backlight):

6 VddI
7 Vdd

The datasheet for PCF8814, however, mentions [2, p. 44] /three/
Vdd pads, with allowed Vdd1 voltage range being (1.7 .. 3.3) V
(presumably meaning 3.0 V + 10% allowance), and Vdd2, Vdd3
ranges being both (2.4 .. 4.5) V.

Looking at the ESD structures [2, p. 66], my guess is that the
I/O voltage is Vdd1, thus 3.0 V + 10% being the upper bound.
But is it connected to the LCD's Vdd or VddI?