2 replies to this topic

[Dave Robinson]

Hi,

 

I created another thread with all the info, but have received ZERO replies, accordingly I am trying here.

 

Basically I want to talk to multiple I2C devices, but cannot.

 

http://forums.netdui...-lcd-i2c-ds1307

 

Please help.

[CW2]

If I understand it correctly, the RTC works fine, but the LCD does not? You said the RTC has I2C pull-ups - do you use external pull-ups when the LCD is connected alone?

 

Have you checked the LCD module IC PCF8574 datasheet to verify the communication protocol is implemented correctly?

 

What is the LCD module supply voltage? In case of 5V, do you use level shifter to ensure proper logic levels from Netduino 3.3V outputs? PCF8574 logic high minimum voltage when powered by 5V supply is 0.7*V_DD = 0.7*5V = 3.5V, so 3.3V is not enough (Arduino is 5V, so that would explain why it works).

 

...but have received ZERO replies, accordingly I am trying here.

It is not unusual to get a reply after a few days, especially when asked during a holiday season; and the probability gets lower for special hardware setups, too general and hard to troubleshoot issues ("it does not work"), without providing at least circuit schematic (photo of the actual wiring even better), the code etc. It's not the community does not want to help you, but there are just too many unknowns...

[Dave Robinson]

Thanks so much for the reply. I will check later tonight or tomorrow.

 

For your info, I have no idea that there is a holiday period happening - there isn't any here right now in Australia.