elipsitz

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1.
by elipsitz 2y ago
Thanks, it's generated with Hugo using the https://github.com/adityatelange/hugo-PaperMod theme. However, I made some modifications to the theme for the first time recently, and learned that I absolutely hate Hugo
2.
by elipsitz 2y ago
Good question, I didn't talk about this in the writeup. It's because I think that this design is the most efficient use of space, if you want to ensure that Game Boy cartridges don't stick out (like they do on the GBA). The d
3.
by elipsitz 2y ago
Thanks! Yeah, support for physical cartridges makes it a complete non-issue. Mappers are a huge problem with the NES, but a much smaller problem with the Game Boy. There are only a few official ones (6 iirc), and one or two unofficial ones.
4.
by elipsitz 2y ago
Yeah, that's another advantage. Theoretically you can get down to <1 frame of input latency with an FPGA. I haven't found the latency on a software GBA emulator running on a computer to be noticeable, but some people might find
5.
by elipsitz 2y ago
Great question! In the absolute worst case (drawing an object at the very top of the screen, and the LCD output for the next frame started right before the current one finished), buffering adds a 2 frame delay (33 milliseconds). Probably no
6.
by elipsitz 2y ago
Thanks for the feedback! Do you mean have it be an entirely different color (e.g. blue), or dim the other inactive headers to make the active one stand out more?
7.
by elipsitz 2y ago
I agree, and wrote a rant about this as part of the post: https://eli.lipsitz.net/posts/introducing-gamebub/#a-brief-r... IMO: the only real advantage is that it allows you to meet the precise timing needed to int
8.
by elipsitz 2y ago
Populated PCB in quantity 100 would probably be 60-70 USD, yeah. Maybe a bit less, it really depends on how much you can buy the FPGAs for. I really did want to switch to the RP2350B, but it's (still) not available to buy. There's
9.
by elipsitz 2y ago
Thanks! Slint has been great to work with :)
10.
by elipsitz 2y ago
I imagine there's a huge difference, legally, with black-box reverse engineering and then creating a very similar design on an FPGA (what I did here), and actually fully decapping the chip and cloning the gates. Plus FPGAs add a lot of
11.
by elipsitz 2y ago
This main distinguishing feature of this project is that it supports physical cartridges, whereas MiSTer and almost every other emulation handheld doesn’t. The FPGA cores here are written from scratch by me with hardware support in mind, an
12.
by elipsitz 2y ago
Yep, that’s definitely a concern with hardware projects. I guess mass produced hardware doesn’t run into the problem as much because there’s funding for upfront bulk component purchases. At least with open source hardware you could theoreti
13.
Show HN: Game Bub – open-source FPGA retro emulation handheld(eli.lipsitz.net)
274 points by elipsitz 2y ago|62 comments
14.
by elipsitz 2y ago
Can’t find an official announcement or datasheet yet, but according to this post: * 2x Cortex-M33F * improved DMA * more and improved PIO * external PSRAM support * variants with internal flash (2MB) and 80 pins (!) * 512KiB ram (double) *
15.
I got almost all of my wishes granted with RP2350(dmitry.gr)
700 points by elipsitz 2y ago|341 comments
16.
by elipsitz 3y ago
I'm not saying that FPGAs aren't interesting, or don't have the possibility of allowing one to produce highly accurate emulators. I think that FPGA emulators are really cool -- I've written one! Check the website linked
17.
by elipsitz 3y ago
Yeah, I guess it's mostly just wordsmithing. But I don't think it's pedantry: by making the claim that their hardware isn't emulation, it implies that it's somehow better than software emulators. There's just
18.
by elipsitz 3y ago
The issue I have is that they’re implying it’s inherently better than software emulation, perhaps because it more accurately reproduces the behavior. But an FPGA emulator isn’t necessarily any more accurate. I think it’s dishonest marketing
19.
by elipsitz 3y ago
But it isn’t a 1-to-1 simulation of the real hardware. Unless they have the original designs for the chips used in the N64, they’re still implementing something with likely very different internals on an FPGA. You can get the same accuracy
20.
by elipsitz 3y ago
Whether it’s a program running on a CPU that interprets software written for the original device, or a configuration of look-up-tables in an FPGA that can interpret software written for the original device, it’s still a system that intends
21.
by elipsitz 3y ago
Sure, it’s not a software emulator, but it’s still an emulator. And Analogue’s use of “No Emulation” is dishonest: it implies that it’s somehow inherently better than a software emulator, which it isn’t. E.g. you can have an inaccurate FPGA
22.
by elipsitz 3y ago
Analogue makes some really cool, well-engineered products. But saying there’s “No Emulation” because it uses an FPGA is blatantly false. If it’s imitating original hardware, without being the original hardware, it’s an emulator.
23.
Show HN: I Built an FPGA Game Boy [Color] Emulator(eli.lipsitz.net)
3 points by elipsitz 3y ago|0 comments
24.
by elipsitz 3y ago
Altera, not Xilinx (owned by AMD)
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Building an FPGA Game Boy Emulator(eli.lipsitz.net)
4 points by elipsitz 3y ago|1 comments
26.
by elipsitz 3y ago
I wrote about what I was doing here: https://eli.lipsitz.net/posts/internet-connected-pinball/#mo... I needed to detect writes to a bus that could happen at 1MHz, which involved reading the state of the bus multip
27.
by elipsitz 3y ago
I had a project where I needed predictable timing for I/O (reading a microprocessor’s bus at 1 MHz), and the ESP32 I was using just couldn’t do it reliably. Despite having a tight loop on a dedicated core with interrupts disabled, a l
28.
by elipsitz 4y ago
Just edited the post to have a link to the GitHub repo: https://github.com/elipsitz/internet-connected-pinball
29.
by elipsitz 4y ago
Fortunately I don’t have to worry about rollover. The game can score a maximum score of 99,999,999, and the highest I’ve been able to score is about 3,500,000.
30.
by elipsitz 4y ago
Thanks! Yeah, it would work on any System 7 game, as long as you’re willing to solder in the 2x20 connector to the MPU. All of the memory locations should be exactly the same.

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