I
Ivan Shmakov
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?
TIA.
[1] http://www.circuitvalley.com/2011/09/nokia-1100-lcd-interfacing-with.html
[2] http://mylcd.sourceforge.net/files/pcf8814.pdf
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?
TIA.
[1] http://www.circuitvalley.com/2011/09/nokia-1100-lcd-interfacing-with.html
[2] http://mylcd.sourceforge.net/files/pcf8814.pdf
