How to use PoPendant and PoKeys in Mach
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4.
Using LCD from Mach
4.1 Connecting LCD to PoKeys
Use HD44780 based or compatible LCD. We are strongly recomended usinf 4 lines x 20 charcters with
backlight. These displays share standard pin-out that is listed in the table below:
Pin
Symbol
Function
PoKeys pin
1
Vss
Ground
GND
2
Vdd
Positive supply (usually 5V)
1
5V (usually) or 3.3V
3
Vo
Contrast adjustment
Variable resistor between GND
and supply or PWM output
4
RS
Instruction/data input
Pin 29
5
R/W
Read/write
Pin 28
6
E
Enable signal
Pin 30
7
DB0
Data bus – bit 0
Not connected
8
DB1
Data bus – bit 1
Not connected
9
DB2
Data bus – bit 2
Not connected
10
DB3
Data bus – bit 3
Not connected
11
DB4
Data bus – bit 4
Pin 26 (or secondary 34)
12
DB5
Data bus – bit 5
Pin 25 (or secondary 33)
13
DB6
Data bus – bit 6
Pin 24 (or secondary 32)
14
DB7
Data bus – bit 7
Pin 23 (or secondary 31)
15
Backlight (optional)
16
Backlight (optional)
Table 2: LCD pin assignments
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Positive supply voltage depends on LCD used. User should find this information in datasheet of the LCD in use.