Fail to control Grove LCD with RGB Backlight on Sodaq Mbili

#1

Fail to control Grove LCD with RGB Backlight on Sodaq Mbili

Hello,

Hardware:
Sodaq Mbili
SeeedStudio ‘Grove-LCD RGB Backlight’ V4.0 connected on Grove I2C socket (12).

Software:
Downloaded Grove_LCD_RGB_Backlight-master.zip from seeedStudio on 23/5/2018 (24,7 KB)
Using only the example sketches from this library (e.g. setColor.ino, Cursor.ino, TextDirection.ino, …)
All the example sketches include <Wire.h> and “rgb_lcd.h”

Compilation performs ok
Upload performs ok

Running the sketches: No reaction of the LCD, only the backlight is continiously on, blue color

Any idea what could be the problem?

Regards,
Luc

#2

Hi,

The SeeedStudio ‘Grove-LCD RGB Backlight’ is a 5V board, the mbili only provides 3.3V
I gues the LCD just doesn´t get enough power.

When the USB is attached there is voltage on the 5V pin. Does it work when you move the red wire to the 5V pin?

Kind regards,
Jan

#3

Thanks for the hint!
I also found schematics with pull ups to SDA and SCL.
Kind regards,
Luc

#4

Problem solved:
Works ok with only external power supply unit (5V) connected to LCD, without the pull ups to SDA and SCL.

#5

Hi,

The pullups are needed on only one side of the lines.
The mbili has pullups on the board, so no extra’s on the sensor side are needed.

Kind reagrds,
Jan