#FPGA SINCLAIR ZX SPECTRUM HDMI PLUS#
#FPGA SINCLAIR ZX SPECTRUM HDMI SERIES#

You can take the FPGA beyond the Z80 with processor cores. FPGA isnвЂ™t emulation: the programmable logic blocks create a perfect representation of the Z80 chip. The heart of the Spectrum Next is a Xilinx Spartan-6 XC6SLX16 FPGA (field-programmable gate array). Some period games become wonderfully playable when cranked up to 28MHz: Sentinel, originally an achingly slow trudge, becomes a fast-paced and tense 3D puzzler. You can also enter POKE files, browse memory banks, and adjust various sound, graphical, and memory settings. The NMI button opens a menu that enables you to flick between turbo modes: 3.5MHz, 7MHz, 14MHz, and 28MHz. And the original Expansion port provides compatibility with classic hardware. To the left of the device sits a full-size SD card slot and three buttons: Reset, Drive, and NMI.

#FPGA SINCLAIR ZX SPECTRUM HDMI PLUS#

ItвЂ™s packed with connections: HDMI and VGA for video out 3.5вЂ‰mm ear and mic mini-jacks PS/2 for keyboard and mouse plus the mini HDMI and micro USB ports of Raspberry Pi Zero and two 9B9 joystick ports (compatible with Kempston, Cursor, and ZX Interface 2 Protocols). The keys are responsive, although the layout is a bit weird after years of muscle memory bonded to PC.

в†і ST 16MHz V1.The keyboard is a thing of beauty.

в†і ST V1 16MHz BOOSTER (Discontinued 2015).

#FPGA SINCLAIR ZX SPECTRUM HDMI SERIES#

в†і ST 16MHz V2.X SERIES BOOSTERS (Discontinued 2020).From what you've said, it sounds like that's going to be the most likely cause of the problem though, and the solution may be to find a new way to detect which is the first scanline in a frame. If that's not it, I'll write a verilog program to indicate what the frame length actually is. I'll have to get it under the oscilloscope and see if DE not taking a break is the problem here. Same principle for vsync: I detect the first scanline in the frame by a DE-to-DE delay of longer than 2048 32MHz clock cycles. But so far it hasn't been necessary because the leading edge of DE is all you need in order to know when a scanline has begun, and therefore if you know how long each line is, you can add hsync near the end. Only the theory that I have read, mainly in Alien's write-up.Д«ecause the shifter doesn't see vsync and hsync, I don't use them at all. Thanks for responding Troed! I don't know much about the ramifications of the overscan techniques in practice. I do manipulate when the MMU sends data (number of pixels per line) of course, but if you're triggering on cycles and not DE then I would think it should work. I took great care when making it to be 'sync clean'. You're correct in that there are many demos that do some scanlines of irregular length (508 cycles - '60Hz', vs 512 cycles - '50Hz') etc, but I don't think В is one of those.

(* Another possibility is that there are scanlines generated all the way through the VBL, so there's no way to tell where the frame begins) The perils of going from analogue to digital. It might not be possible to support a video mode where each video frame is a different length, or if some scanlines are longer or shorter than others.

But it means a lot more work will be involved. I hope not, because right now my implementation is based around the three normal video mode timings: 896x501, 1016x262, and 1024x313, and it's a fair bit of work to change it.ДЄt the end of the day, it should still be possible to support everything that the Atari can throw, by storing all the measured video timings in registers and then basing the output video format on that. It could mean that each programmer, doing their own overscan implementation in a slightly different way, could come up with a different video mode from every other programmer. But I didn't realise that the actual length of the scanlines (or the number of scanlines in the frame) would change! I know that the line frequency is toggled in order to skip over the part of the pixel or scanline count where the MMU would normally decide when to stop sending data. I'm not sure what the exact count is, but I obviously need to do a lot of research into what is actually going on in the machine before this can be displayed. I think that means the total cycle count for each frame is not one of the standard ones* (50Hz, 60Hz, 71.2Hz). My FPGA lost sync with the incoming video data, which means it couldn't track the correct number of CPU cycles between DEs. I got around to testing this, and another demo that uses overscan, and I discovered something interesting, and annoying.

Fpga sinclair zx spectrum hdmi