The program is a modified version of Joe Savage's awesome Writing a Game Boy Advance Game example of how to write a GBA game.

Frame Test ROM can be used to test that your GBA's display driving is working as it should. It's mostly useful for people changing their console displays to 3rd party models e.g. "IPS V2". These displays are coming from several vendors and with varying quality. Some models can have display tearing or are missing frames. With the test ROM you can see how well your display works.

Install test ROM to your GBA. You need a flash cart or similar solution. Start the ROM and you should see vertical block going from left to right over and over again.

Example video of Gameboy Advance SP with original AGS-001 display recorded with 480 FPS from YouTube. Like all the original displays it shows the scanline pattern.

Here is a slow motion example of 3rd party IPS V2 display showing frame drops. IPS displays do not use scanline pattern but draw the entire screen at once.

Take your phone and record the screen with the quickest slow motion video recording mode you can find. For example 240 or 480 FPS will do nicely.

Then inspect the video to see that there are no missing frames. Since the block moves one step every frame you should be easily notice that if it sometimes jumps more which means you had a frame drop.

You can also test if the screen is tearing. It happens when the display was still drawing the vertical block but the driver doesn't synchronize the process correctly and jumps to next frame. Visually it causes a vertical discontinuity in the image.

Tearing is not to be confused with normal banding with original scanline displays (AGB-001, AGS-001, AGS-101) when watching slow motion footage since these displays draw line by line from top to bottom.

You can find ROM binary from release page.

You need devkitPro for GBA.

See build.sh.

• "Logo is corrupted and boot fails"
  • See issue and a solution at Boot fail using Everdrive GBA