[HELP] I2C LCD with STM32F4-07VG and CooCox

[Mugle_ENSPARTAN]

Hello all. I have a problem with my lcd. I use it on our robot to see a parameters on robot with STM32F4-07VG board.

I used lcd 4x20 with i2c wiring and pcf8574 module and also coocox to program it with library from www.stm32f4-discovery.net

The problem is, the lcd is often send the random data (not like there isn't same the baudrate), the text is running random from up to bottom. So i have to reset the board so the lcd will display right text and static text (not running text).

I dont know there is problem with my program or my wiring lcd. Because the case is randomly happen. Sometimes it's happen when the robot have a tremble, sometimes it's happen when the robot is motionless.

Maybe someone know about this problem and can explain to me, thanks

*video/pic when the lcd error is come afterward

 

[NV64]

Maybe someone know about this problem and can explain to me

Looks like a strong electromagnetic disturbance. Is there a high voltage/current source nearby?

 

[rjenkinsgb]

My first thought would be too long connecting wires, causing either voltage drop or transmission line type effects and corrupting the data.

How long are the wires and (if more than a few inches) how thick and what physical arrangement?

Or it could just be a faulty display or bad connection...

 

[Pommie]

Are you able to reduce the speed of the I²C and see if the problem goes away?

Mike.