Former ASM coder from HP48

Welcome aboard @Brizzlyy … if you can write assembly for a calculator, I am sure the learning curve for you to master the Arduino / Arduboy environment is going to be child’s play.

As already pointed out, start with @crait’s series and have a look at the Arduboy Magazine

1 Like

Yeah cool I already know pretty well C++ as I already wrote many projects and games with this great language :slight_smile: Cool !
Does one know if a future new arduboy with 4 grayscales like GameBoy display’s will be built one of these days ?


There are a number of threads on here with people’s wish lists. Two colours sound like a limitation but there are some impressive games out there. Of course, if you are trying to migrate something you already have be prepared to redo the graphics if they are currently 4 gray scales.

1 Like

On HP48 we did hack the display controller to flick 2 bitmaps in order to make 4 grayscale. I’m pretty sure the Arduboy’s OLED display could be hack the same way using interrupt handler and the VBL.:wink:


Attempts to do this have been disappointing, mainly because there is no way to access the VBL timing. There has been limited success for some very specific situations.

Nice ! Almost perfect, I think the vsync should be hardware based on such OLED screen.

The display timing is independent of the CPU clock and no display timing signals are available, including vertical sync. You’re welcome to attempt grayscale yourself, though.

The display documentation is here:

Better wait for another version of Arduboy 2 with this kind of display, still retro but with 16 shades of grey :slight_smile:

It’s unlikely the Arduboy will use that screen.
Bateske Has expressed that he wants to make sure the Arduboy stays credit-card sized, and that screen is far too wide (nearly 8 cm).

Besides which many people have asked specifically for only 4 shades of grey (and others are completely opposed to greyscale and want to keep the screen black and white).

Indeed just keep in mind the exact credit card screen size with 2 and up to 4-colors grey scales capability, killer feature and just like the Game Boy… :wink:

@Brizzlyy, Then it’s up to you to find a suitable and available 2 or 4 greyscale display with at least 128x64 pixel resolution, that would still allow the credit card overall size, where everyone else has so far failed to.

I wonder why this is so hard in 2017, we did that in 1993 on HP48 SX calculator not to mention Gameboy.


The HP48 display is too large for a credit card size. The Gameboy display is likely too large as well, especially the height. And, are either of them available for purchase today, in quantity, at a reasonable price?

It’s not a problem of it not being technically possible. There just aren’t any available as a standard part. To have a display custom made usually means that you need to order a minimum quantity in at least the 10000 range or maybe even more than 100000, which is too high a risk for something like an Arduboy 2.

I understand. Thank you for sharing it’s very interesting.
Btw the HP48 screen is actually smaller than a Credit Card (131x64 pixels).

So is the Gameboy screen but neither would leave enough room for decent size buttons if you wanted the whole thing to be credit card size.

1 Like

131 x 64 … that’s almost the same size as the Arduboy. Should make the conversion pretty simple.

Why 131, I wonder?

1 Like

The Saturn architecture is nibble-based; that is, the core unit of data is 4-bit-sized, which can hold one binary-coded decimal (BCD) digit.

The Saturn microprocessor is a hybrid 64-bit / 20-bit CPU hardware-wise but acts like a 4-bit processor in that it presents nibble-based data to programs and uses a nibble-based addressing system.

The screen is 34 X 4-bit memory sized width (like 136 pixels) but only 131 real hardware pixel width displayed.

1 Like

So are the other 5 pixels are overscan or not actually wired up?

overscan, you have to move your pointer to 34 “4-bits” nibbles to go ahead to the next line of 131 pixels :slight_smile:

1 Like