Image: SNK

FPGA developer Jotego has been working on his Neo Geo Pocket core for quite some time and had set himself an informal deadline for the release of its beta version. That deadline is today, but sadly, the beta is not ready for release as yet.

"I set this deadline to force myself to focus solely on this project," says Jotego in a recent update. "The core has seen a lot of progress and it boots up and runs through the language and clock set up screens. However, it hangs up soon after."

He goes on to explain some of the issues he has run into whilst developing the core:

During these three weeks I fixed several bugs in my T900H CPU core and also implemented other parts of the NeoGeo Pocket system which were missing, such as the timers, the fake battery indicator and the sound subsystem. The biggest missing part from the NGP point of view is the DMA subsystem, but it does not seem to be used by the firmware.

Like it happened with Haunted Castle, there seems to be a pending bug in the CPU implementation that is halting the progress at the moment and it is going to delay us a bit. This bug occurs during the setup screens as part of the text is not at the right position (because of the CPU). This may also be the reason why the system hangs up later on.

There are two other features currently missing from the beta:

JTFRAME only supports one ROM per system at this moment, which means that it would only load the firmware and not the cartridges. Some people asked for using MRA files for this core too. That would work with JTFRAME as it is, but it would require writting over 70 MRA files. Probably the approach used by the other console cores is more practical for everyone.

Displaying on a CRT/HDMI screen. I originally thought that the image was to be drawn on the screen as the circuit renders it. That would make it very cumbersome to port to a different technology as the timings used in the NeoGeo Pocket LCD screen are very different from those of a CRT or HDMI screen. Nonetheless, it looks like there is a frame buffer between the screen rendering and the LCD displaying it, so that will ease the problem. This part of the system is not implemented yet.

Jotego concludes by saying he's unsure of how much longer it will be before the beta is ready for release, but he adds that "it’s clear that we are very close."

He says the aim is to continue working on the beta core for the foreseeable future, but one week will be set aside for him and his team to work on a new arcade core beta.