9 replies to this topic

[Arron Chapman]

I have an LCD (16x2) because I didn't want to give up so many of my precious pins I also purchased the LCD Backpack, However I cannot figure out how to make it work. Any direction would be greatly appreciated.


On a slightly side note, are there any super basic tutorials using Serial communications with a Netduino? I think that some super basic/simple tutorials are one of the few important things missing from the community. If they are out then they need to be made easier to find.

[Fabien Royer]

The backpack requires requires 5V TTL, so with the netduino, you're going to need some form of level-shifting: you could use something as simple as an NPN transistor driven from the TX pin of the netduino.


Cheers,
-Fabien.

[Hinnie]

Fabien Why do you write that level-shifters are required? In the tech specs is written "digital i / o are 3.3 V - 5 V tolerant but" I think that the level-shifters are not needed. Or I read that wrong? Hinnie.

[bill.french]

Do you have code you can post, or you're not sure even how to start with code? I'm thinking it is going to work fine w/o 5v ttl -- the "5v tolerant" means the netduino can tolerate 5V *input* -- output is going to be 3.3v. Check out the code attached to this post: http://forums.netdui...ch__1#entry5962 ...it's the best I have for serial communication.

[GDSever]

I haven't had any problems sending 3.3V signals to a 5V serial backpack for LCDs. I've tried out a couple of them (Wolfden.org and one direct from PHAnderson), and both worked just fine without logic level switching.

[Arron Chapman]

@bill.french I'm not quite sure where to start. I feel like there is quite a lot of the basics regarding the Netduino that I don't know.

[Fabien Royer]

I haven't had any problems sending 3.3V signals to a 5V serial backpack for LCDs. I've tried out a couple of them (Wolfden.org and one direct from PHAnderson), and both worked just fine without logic level switching.

I've had a different experience in the past using Modern Devices' serial backpacks: http://shop.modernde...x4lcd-lcd117kit They would not respond to 3.3v inputs w/o level shifting.

[Fabien Royer]

UnkwnTech,

I wrote a post showing how to deal with level-shifting, using the 5 volt LCD backpack as an example: http://fabienroyer.w...ith-a-netduino/

I hope this helps.

Cheers,
-Fabien.

[Arron Chapman]

UnkwnTech,

I wrote a post showing how to deal with level-shifting, using the 5 volt LCD backpack as an example: http://fabienroyer.w...ith-a-netduino/

I hope this helps.

Cheers,
-Fabien.

I saw your post earlier, thanks, I promptly ordered several (25) of the level shifters .

[Fred]

I ordered a 3.3V LCD with SparkFun serial backpack from SKPang. Whilst the backpack was labelled 5V it worked fine - including being powered by 3.3V. I assume it works with wither voltage and you only need to worry what voltage the LCD is expecting.