Basic pocket computer display modification

original? what do you mean?

These files.

this is the same code that i originally used, but it still does not work. this is written for a 16 by 4  not a 20 by 4.

Did you use the 4 bit monitor?

Ah, you probably need to re-arrange screen memory so it doesn't overflow the lines.

Look through the code for instances of 16, or multiples thereof.

Ah, you probably need to re-arrange screen memory so it doesn't overflow the lines.

Look through the code for instances of 16, or multiples thereof.

crossposted to a new thead

I am too having problems getting my 20*4 screen (https://www.sparkfun.com/products/9568) working. I tried changing anything I could imagine having anything to do with the number of  columns in the lcdChar (), doFrame () and setup () routines. Do you know which lines exactly must be changed in order to get a clean output?

thanks.

___________

Edit (13.8.);

I got it PARTLY working! THE 4 RIGHTMOST CHARS IN THE FIRST LINE ARE STILL MISSING AND DISPLAYED AT THE BEGINNING OF THE THIRD LINE. Anyone got help? For anyone who wants to know how, I changed the following lines in Tinybasic_2.ino (you find it here: http://www.element14.com/community/thread/25177?start=14&tstart=9)

WARNING! I DO NOT HAVE ANY HARDWARE TO TEST THIS WITH! THIS MAY STILL BE BROKEN!

tl;dr

Now that that's out of the way, here's a (potentially) fixed copy of the script:

https://gist.github.com/zanothis/9167288

I had to make the fixes using only the code and the algorithm contained therein. The lcdChar function had a few things mixed up.

The original used the following:

for (int xg = 0 ; xg < 16 ; xg++) {

screenMem[0 + xg] = screenMem[40 + xg];

screenMem[40 + xg] = screenMem[16 + xg];

screenMem[16 + xg] = screenMem[56 + xg];

screenMem[56 + xg] = 32;

}

This seems to be trying to handle the interlaced copy of the display lines. The problem is that 40 is valid for a 20x4 display, while the 16 would be useful for a 16x4 display, and the 56 is useful in neither.

If you need to, picture the 1-dimensional array as it will be displayed where the number values are the array indexes (16x4 used, though the same applies to 20x4):

0 ... 15

32 ... 47

16 ... 31

48 ... 63

The algorithm should be written as follows:

for (int xg = 0 ; xg < 16 ; xg++) {

screenMem[0 + xg] = screenMem[32 + xg];

screenMem[32 + xg] = screenMem[16 + xg];

screenMem[16 + xg] = screenMem[48 + xg];

screenMem[48 + xg] = 32;

}

Then screenMem only needs to have a size of 64.

There are also several places that call doFrame(56) that should actually be doFrame(64). Line 1471 is an exception and should be:

doFrame(48 + cursorX);

Once those changes are made, changing to any other size is as easy as changing all the 16s to 20s, the 32s to 40s, the 48s to 60s and 64s to 80s in the case of a 20x4 display.

I didn't realize there was so much interest in this!

My original code was quite the kludgy hack (which is common when you only have a few weeks)

BASICally, the interpreter is meant to output via serial. I followed the chain down to a single serial print char, and rewrote that part to instead fill that data to "screen memory"

The trick is once a Hitachi 44780 goes past 2 lines the lines aren't numbered sequentially (they are interlaced)

On top of this, for the display to coarse scroll, it needs to keep track of the data.

A more elegant solution would allow you to set constants of DIisplay Size, so it would know the width of lines.

Hello Ben i been following your videos for some time now and i must say you are doing a awesome job man. I know a lot of hard work  that i not  show in the videos. i just recently developing a pocket pc using arduino. and i looked at your coding and you did a awesome job thank you. i have a hard time coding or hardware of things or to even get started my self but watching your videos it help me a lot thank you.

Your project is great.

I am still working on it, but for some reason the LCD is still not working.

I already developed a driver (based on the work on Cliffleblog) for the Chatpad, but the LCD is just not working.

Here are some photos of the LCD and the project components.

The mega will later be replaced by a single ATmega328p and the blue LCD is going to be replaced by a green one (HD44780, 20x4 aswell).

I hope anybody, including Ben, whose show I really like and follow since years, can help me solving the LCD problem.

I am using the code from github that was posted earlier here in this thread.

Greetings, Muessigb