A real FM-7 on the left and the MiSTer core on the right.

In a recent discussion with Solal (retro gaming) about arcade backbuffer techniques, we discussed the following methods: DMA, pointer swapping, and memory swapping. Did we forget any?

Just got the first screen of my little summer FPGA core project, coded on my phone at the beach🩴🏖️

I hooked up PROM and fixed values for the color resistors. I need to look at sprite decoding now.

I'm rewriting some of my guesses with better chip implementations. I'm working on the Konami 504, which is mainly a 6809 E/Q clock divider. I'm only writing HDL, someone else reversed it. It seems to work! 😊

End of vacation, time available for MiSTer = ε 😭

Pandora's Palace has 24 hardware sprites, but the title screen shows up to 38 sprites at once. This is possible thanks to the Konami 85 scroller chip, which has a vertical read pin. The CPU uses it to track the scanline position and reuse the slots of already rendered sprites.

Another technical detail about Pandora's Palace: they set the four upper bits of DX bus (sprite X/Y) to high impedance (COL signal) to insert the H/V flip flags from DC in time (blue), ensuring the Konami 503 captures them correctly, since the attribute byte never reaches it.

I spent several weeks working on a RISCV32 CPU, and now I can boot Linux! 🙂 It's just a software simulation for now.

It seems one of these documents might contain the full source code of the TMS7000 microcode. Does anyone know where I can find the microcode listing? - TMS7000 Micro-architecture - TMS7000 Microcode Development Users Guide - TMS7000 Micro Assembler

I try to rebuild the TMS7000 microcode ROM, mostly guesswork😒Frustrating that the listing exists in TI’s archives but hasn’t been scanned yet...

Thanks to the kindness and professionalism of the staff at the DeGolyer Library SMU Libraries, I finally gained access to scans of the TMS7000 Microcode Development Guide from the Texas Instruments archives! 😀

I used to think we needed broad knowledge to build custom tools when porting hardware to FPGA. Now, with AI, a few prompts give us everything we need🙃

This is so cool! Thank you Pmaxsd