raspberrypi_aqm0802_print

Shellscript for the AQM0802 charactor LCD on RaspberryPi.

settings

item	descriptions
I2C_BUS=1	I2C bus No.
LCD_ADDR="0x3e"	LCD I2C slave address

usage

execute with one arg that is strings.

[pi@raspberrypi]% ./print_aqm0802.sh "hello   world"

you can see "hello world" in the LCD.

software requirements

• bash
• od
• head
• sed
• cut
• i2cset , i2cget

hardware list

• RaspberryPi, OrangePi C.H.I.P. and i2cget/i2cset working environment.
• AQM0802 , AQM1602
• 2SA1015 (or other PNP tr)

hardware connection

 AQM0802                                 RaspberryPi
+--------+                                +-------+
|        |                                |       |
|      VDD---*----------------------------3.3V    |
|        |   |                            |       |
|    RESET---+                            |       |
|        |                                |       |
|      SCL--------------------------------SCL     |
|        |                                |       |
|      SDA--------*                 +-----SDA     |
|        |        |                 |     |       |
|      GND---*----+-----------------+-----GND     |
|        |   |    |                 |     |       |
+--------+   |    |                 |     +-------+
             |    |                 |
2SA1015      |    |                 |
+------+     |    *--[R 100k Ohm]---*
|      C-----+    |                 |
|      B----------+                 |
|      E----------------------------+
+------+
(PNP Tr)

+ corner/cross-over
* connect

PNP Tr wrokings

AQM0802, AQM1602 is lower sink power at SDA. they can't drive-L at I2C bus (SDA). Therefore I2C communication will fail.
PNP tr is help this problem.