Trying to understand LCD displays


Up until now, I’ve only ever used character displays so I thought it was about time I gave an LCD a try and bought an N18 module.

However, I’m a little baffled as to what’s going on with mine. When connected to my Hydra+ and using the following (gleaned from the graphics document);

this.displayN18.SimpleGraphics.DisplayEllipse(GT.Color.White, 1, GT.Color.White, 5, 5, 5, 5);
this.displayN18.SimpleGraphics.DisplayLine(GT.Color.White, 1, 20, 20, 40, 40);
this.displayN18.SimpleGraphics.DisplayText("Hello, World!", Resources.GetFont(Resources.FontResources.NinaB), GT.Color.White, 60, 60);

I get as shown in the attached image.

The double display is the first thing that I don’t understand but also, it’s not completely evident in the photo, the first line is blue and the second is red. There are also some red pixels visible around the first ellipse and the text.

Any help is much appreciated.

Additionally, this;

this.displayN18.SimpleGraphics.DisplayRectangle(GT.Color.White, 1, GT.Color.White, 0, 0, this.displayN18.Width, this.displayN18.Height);

Gives me this;

how do you initialise it? is there any?
also make the rectangle again at half the screen width please

I’m testing as a gadgeteer app, so it’s initialised in the generated method ‘InitializeModules()’. It all looks OK when it is initialising, the whole screen is white briefly.

This is how it looks with the width halved;

Gives this;

A quick check with

Debug.Print("Screen Width: " + this.displayN18.Width.ToString());
Debug.Print("Screen Height: " + this.displayN18.Height.ToString());


[quote]Screen Width: 128
Screen Height: 160

Also, doubling the height does not fill the bottom half of the screen so I’m guessing that it is starting from half way up the display.

It’s a known bug in the current SDK that has been fixed in the next release.

Take a look at this thread for a temporary fix.


So who, at GHI, do I send the bill to for my wasted time? :wall: :wink:

Is that definitely the same problem that I have here because that bug is described as ‘the DisplayN18 on non-cerb boards and the TakePicture functionality of the camera’? Or are we saying that it’s more specifically just an issue with the N18 and non-cerb boards?

In all seriousness, for a platform that is heavily target as educational, and for it’s simplicity, this kind of thing is a real kick in the gooleys. Surely there is better way of handling these bugs without having to go through the pain of finding out for oneself or trawling through forum posts? There is no mention of any of this in the N18 documents. And we could now have to wait up to 6 months for a proper fix? That post was made 4 months ago!! It all seems like a backwards step to me.

If I downgrade to R4, which seems like the most sensible option, will I have to reflash the Hydra+? In the chanelog for R5 it says that there is a fix for LCDs on the Hydra so that’s definitely a backwards step…

wolfbuddy. it’s two known bugs. One with the camera, and one with the n18 display.

I agree with you about the seriousness of the bugs, but I was told specifically that “neither of those two bugs was serious enough to warrant an unscheduled sdk release.” or words to that effect. They are trying to minimize the number of SDK releases.

I get the idea though, that the next release is fairly soon (not several months) so I am hopeful. A logical time would be at the end of each quarter (end of March) although nothing concrete has been said. That’s when I am (not so) secretly hoping it will be.

And while you could try sending your bill to John, I’m pretty sure he feels bad about his n18 bug.

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it’s two known bugs[/quote]

Known to who?! Certainly not a potential customer because there is nothing about this in any of the documents that I can find.

To discover that this has been known about for many months and still is neither fixed nor clearly noted makes me very annoyed.

Well, it’s quite obvious that’s a bad idea!

Additions and improvements can be scheduled, bugs should be fixed promptly.

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