Digging into the MISTER PI

[@brenfu]

Just wanted to say your video, and the other QMTech Mister one I watched, are superbly made and very accessible to someone like me with only the vaguest understanding of all the tech involved. Lots of short cutaway close ups and highlighting of parts/pins are so brief to almost go unnoticed but give a perfect visual reference of what's being discussed. The time and effort put into this is appreciated, thank you.

[@whatskenmaking]

Thank you! I always appreciate when the little details are noticed 😊

[@bobbus_74]

I second this. Great video for the uninitiated.

[@kennethd4958]

Love my QMTech “clone” Mister. With built in 128mb SDRAM and getting the board, analog IO board with USB hub and case all for under $170… it’s a retro enthusiasts dream come true.. especially since a couple years ago I paid almost $450 for the same thing with the original Mister FPGA.

[@boogernetwork]

The SPI Flash chip is to burn a bitstream on it so the FPGA can load it during boot, they're usually named EPCQ-A devices. The usage is controlled via the the MSEL dip switch, that set up how the FPGA should boot (via SD Card, SPI Flash...), mister doesn't function with it since it boots the HPS first and the bitstream is managed by it.

[@radicalbyte]

So Taki could remove it without issues? :)

[@Overdose140]

⁠@@radicalbytebut why would he want to remove it when it gives you the ability to boot from different sources? It is definitely there for a reason. This board is not just for gaming!

[@radicalbyte]

@@Overdose140 Taki's board very much is targetting gaming.

[@quantum5768]

@@radicalbyte It's quite possible that it was included solely because it's on the DE10 Nano board. A common use case for SPI flash is bitstream storage as already mentioned, but some FPGA designers go one step further and use the SPI flash at runtime for extra storage. It's plausible that a Mister dev may in the future use that SPI flash for that reason, and the Mister Pi not having it would stop users from using those cores. I''m an FPGA designer myself and I'm happy that the Mister Pi is still good as a general purpose dev board, it's often way faster to just program/debug an FPGA via JTAG/SPI flash than using the OS on the CPU side to flash it. I just so happen to work with a Xilinx SoC similar to the Mister and having to go via the operating system to test a new design is really slow by comparison to the more traditional approach.

[@RetroRockGamer]

I really appreciate these deep dive videos.

[@RichRap3D]

Hi Ken, Great video and dive into the Mister Pi. I can answer one of your questions - we do use the 9V output from the DE10-Nano in the Multisystem - it's specifically for control signals on the SCART connector - auto switching for a standard European TV set. I did mention to Taki about this voltage, but I'm not sure if they included it because the original DE10-nano has if or is any other expansion I/O also uses it. We have done a lot of testing with the Multisystem I/O motherboard and are happy to say the Mister Pi works well with the Multisystem, I'm very happy they did include this extra voltage signal. Also worth a mention that the SDRAM memory IC's are rated at 133Mhz and no MiSTer core (other than the memory tester) uses the SDRAM at a speed over 130Mhz so having a memory module that is stable at 150Mhz is fine, but not useful for MiSTer. Most suppliers including us run the memory at 140Mhz for stability testing. Also if you run the memory modules at 150Mhz for many days, you should start to see red errors clocked up - not many but you may see 13 over 4-5 days. (we tested both QMTECH and MisterPi in this way for 1 week of operation in both 25 Degrees C and elevated 30 Degrees C ambient).

[@whatskenmaking]

Very insightful as always! Although I own an MMS, I’ve never used SCART and didn’t realize that it used 9v. Great to hear that the MPI is compatible with it!

[@grumpyoldgamerUK]

Great video Ken. Its nice to see proper technical reviews like this

[@MarceloMedeirosb]

This was a very well put togheter video, both the content itselft and the production as well. Good job!

[@geofreypejsa54]

Awesome. More mister content! Thanks Ken

[@lsdowdle]

Still waiting for your DIY handheld MiSTer FPGA video. I'm sure it'll be something way beyond my technical capabilities to make but am interested in witnessing the magic.

[@whatskenmaking]

It's finally in progress! 🥳

[@dekky3908]

​@whatskenmaking Looking forward to that video too.

[@lordbacon4972]

I was lucky to get a MiSTer Pi on release day 1. It's really fascinating to learn all the things you examined -- i'm powering it using the usb ports from my power bar (it negotiates 5V, 1.2A). That flash dump is intriguing mystery -- I hope someone finds out what's the purpose for it.

[@flow221]

Excellent overview, thank you.

[@bootsector_]

IIRC, that micro SD card corruption turned out to be a power issue caused by a bad USB-C cable (I think the one provided by Taki)

[@whatskenmaking]

Interesting!

[@vitorbotossi]

Great video Ken! Looking forward for your handheld DIY soon!

[@whatskenmaking]

Thanks - Hopefully the next video!

[@BrunoFonsecaPT]

Very cool in depth comparison. Great job!

[@Michael_john_mentzer]

love the work ill def check this board out later, thank you for making this

[@speedlolita]

I'm using a Pi 4 PSU to power mine to avoid that excess heat. Working well for my application so far

[@jstro-hobbytech]

your channel is growing brother. it's good to see. i've got some video game stuff if you want it man. i have some launch ps3 consoles that need repair and love and i dont need 5 ps3 consoles haha. they all boot but the cases are kinda poopy be a cool project. it needs to be remarried to a bdrom without the original daughter board. you could print a custom case for it and make a cool video fixing it. i fixed 1 already but my repair queue is huge. i'm doing alot of coding and writing music / restoring guitars and vintage effects processors. i'm in nova scotia but itd only cost me 45 beans to send it if our postal service ever goes back to work. im trying to offload a bunch of stuff from my electronics bench / gaming room / recording studio haha. no strings attached. i like how good you explain stuff for beginners but you are in depth enough for more advanced people to learn as well. i like seeing good creators succeed.

[@wiesman2613]

Great deep dive, I was able to get a misterpi on the first run (even though I had to wait a month for it to finally arrive 4px shipping is awful) I'm loving it so far. Definitely worth every penny of the $160 I paid.

[@william18miller]

You should test the Analog Audio output. I was one of the unfortunate who discovered it had muffled audio because they had installed the wrong resistors on the L-shaped board of the AV Pro 9.2. Sent it back to Taki and they sent me the correct one back and all is well now

[@whatskenmaking]

I did play a bit with the analog IO board and didn’t notice any muffling, so I was probably using one of the corrected boards.

[@rentoptional1524]

Great advice on the USB PD boxes. I was using an anker one on mine for no reason other than availability. I switched it to another basic one i got with my Google pixel to prevent the potential heat issue.

[@phillai]

I was lucky to get hold of the MiSTer Pi and I had slight SDRAM problems but Taki responded really fast and is sourcing me an SDRAM replacement! Great MiSTer Pi video as always Ken but can I be cheeky and ask for more FPGA videos on your channel! 🙏 P.S. That UGREEN SD Card Reader phone stand looks fantastic!! 👍

[@whatskenmaking]

I have a few new FGPA things on the way, so there will be some more non-MiSTer FPGA content over the coming months.

[@coolbho3000]

I think the MiSTer Pi and QMTech boards may actually be running the memory at the same latencies as the DE10-Nano. I have a shell script you can run to check all the primary and secondary RAM timings on these boards.

[@mzaite]

I love this new affordable unobtanium economy for tech. “It’s cheap! You just can’t get one!” Well at least I don’t feel ripped off or priced out of the market….so it’s an improvement from the COVID economy.

[@troymeredith521]

Taki actually made an update today explaining the lapse in opening it up for new orders. Looks like next batch is coming soon though, so good luck.

[@PixelCherryNinja]

Thanks Ken. Great video.

[@ToddsNerdCave]

Awesome video and lots of great analysis!

[@MRooodddvvv]

The whole point of FPGA is it blank sheet where one can "draw" the "logic schematics" of a device which fpga should represent. Later (during operation) it is stored inside fpga but type of cells where it is stored is volatile so it is only there until power applied. Once you remove power fpga become blank sheet again. So after every power up it need to load its "design" (mister core in our case) from somewhere. and normally it is SPI flash because something like SD card is way more complicated to communicate with and do automated load. So pretty much EVERY board with fpga contain SPI flash. There are some exceptions like older PLD devices which had onboard flash storage and before wide spread of using normal SPI flash for this some proprietary interface serial flash chips was used. Also relative new fpga which like cyclone5 contain onboard hardware ARM core could implement necessary bootloader in tiny one time programmable or on-chip mask rom to load fpga design from SD card by software on ARM core. SPI still way to go for most of applications.

[@whatskenmaking]

Right, that’s why I would expect a flash chip for a typical FPGA dev board like the DE10-Nano. But the MiSTer loads from the SD card over the HPS, so the flash chip isn’t necessary for a purpose built MiSTer FPGA board. QMTech’s board doesn’t have the flash chip, for example.

[@LimbaZero]

@@whatskenmaking Maybe they included it to keep board also option for developers/hobby fpga users because normal/official devkits are expensive. Some times those only play around with FPGA portion and don't use ARM so in that case config flash is needed.

[@Vermilicious]

Not a big fan of the way these things need to be stacked high. Would be neat if someone could make a single-board variant with the most commonly used bits and bobs.

[@mirabilis]

If someone did that they would also have to create a custom case, no?

[@squidware]

Micron website showed a search for FBGA What's that, Field Brogrammable Gate Array? Just like a FPGA but throws bruh errors every 5 seconds

[@whatskenmaking]

Ha! FBGA = Fine-Pitch Ball Grid Array. Rather than printing long product codes in small font on those chips, Micron opted to use short codes in combination with a decoder

[@_warky]

Im curious as to why he didn't use resistors to negotiate 5v. It's a lot simpler.

[@Е.А-н9э]

Hi! Great review 🙂. Unfortunately, everything is sold out. Can I buy it soon?

[@billford171]

only issue I have had so far with the MisterPi is the SD card slot is really, really tight. hard to get the card in and out, but everything else seems to work the same as my original mister

[@emmettturner9452]

I read somewhere that the Commodore Datasette uses 9v to power the motor. Antonio Villena makes a MiSTer adapter that replicates the C64’s serial port along with the Datasette user port to power the SD2IEC. Maybe the SD2IEC needs 9v and the adapter supplies that? Doubt it since his adapters use the same DB9 with 5v.

[@whatskenmaking]

I don't think that's the case - Antonio's device doesn't connect to any of the headers that output 9v

[@bruce_just_]

no, not 9v (9v AC?) The motor needs around 6v to operate, which is derived from the 9v AC supplied from the external PSU. It’s generated through a transistor stage adjacent the C64’s cassette port. I’d presume that Antonio’s C2N/IEC DE9 adapter board for his specific MiSTer IO board is doing some level conversion to start/stop the C2N’s motor according to motor line in the FPGA core.

[@emmettturner9452]

Thanks. I believe he is only using it to power SD2IEC devices that get their power through the user port so perhaps it also has 5v and that’s all they need.

[@grumpyoldgamerUK]

The SNAC IEC adaptor is for IEC disk drives or printers There is no support in the core for real tape drives and the core has no tape control either Antonios SNAC board is the only one available with a tape connector too

[@chrisglover4360]

Any luck finding a heat sink small enough for the MiSTer Pi's buck converter? I haven't been able to find one smaller than 6x6mm. Thanks for the video and info.

[@DryadMachine]

Thanks for the video Ken. I've been eagerly awaiting it since getting my board. I've just ordered a Pi 4 PSU because of your findings. I have been using a PD charger that has the same specs as the one recommended on the Retroremake website so it has likely been putting out 12v. Did you find out what the red led next to the HDMI port is for?

[@whatskenmaking]

Glad to hear that you went the other route! I didn't notice the LED next to the HDMI port, and I've already packaged it up to send back to Koala

[@stanislavponomarev8829]

well there is no schematic available as you mentioned, but the contents of this flash chip is most likely an fpga bitstream cyclone V soc fpga fabric can be programmed in 4 different ways: 1) through JTAG header / onboard usb blaster if it were de10-nano 2) through HPS (Hard Processor System, the ARM CPU) - this is how MiSTer loads its cores 3) through Active Serial flash chip - this is Altera-specific kind of a flash chip, de10-nano has an EPCQ chip, but it can cost up to 10$ so no wonder it is missing on both qmtech and MiSTer Pi boards 4) through Passive Serial flash chip - well this is a cheap alternative to having an AS chip. i suppose a generic cheap SPI flash chip can be used (like the one you found) and if my guess is correct, this board is a bit more convenient to use for development than the qmtech one upd: dont worry, on de10-nano (or clones) how the fpga starts up is configured by those tiny 5/6 dip switches, AS/PS chip wont be used unless you set them correspondingly, which will prevent MiSTer from working upd2: you can try to set MSEL[4:0] to one of PS values and see what happens 🤡 it should be [OFF, ON, ON, ON, ON, *] or [OFF, ON, ON, ON, OFF, *] - sixth one is not connected

[@39zack]

Did you ask Taki directly about the mystery chip?

[@thaKingRocka]

Is it just the 5v that makes the difference in the heat on that converter? Would a 5v 4a produce significantly different results from a 5v 2a PSU?

[@HisVirusness]

Great video; it was very detailed and well demonstrated. I know I'm not the first person to say this, but I'm wondering about the prospect of an open hardware version of the DE-10 Nano. We have clones of it now and conceptually, a more DIY approach could possibly be more accessible, and cheaper, to those wanting to get into the MISTer project. The only problem is feasibility. Do you think something like that could be feasible now or some time in the future?

[@whatskenmaking]

It's interesting - both the DE10-Nano and QMTech boards have their schematics publicly available, so I don't think there's anything preventing anyone from going off and reproducing them. But I'm a bit surprised that no one has built an all-in one MiSTer device so far with everything integrated into a single board. Could it be cheaper than a full stack setup (dev board + SDRAM + analog IO)? Possibly, but probably not enough much less expensive than the QMTech or Retro Remake full stacks.

[@flomojo2u]

​@whatskenmaking I'd think it would be interesting even if it wasn't cheaper, I own an original MiSTer and all the extra boards and adapters are really annoying. Having a single integrated board with USB-C connectors would be amazing!

[@red2]

Nice comparison, what about the audio sounding a little dull on the some Mister Pi IO boards ?

[@whatskenmaking]

I didn't notice anything out of the ordinary, but I don't have a great ear for audio

[@phillai]

One more thing, what makes the DE10-Nano GREAT in comparison to MiSTer Pi GOOD with the accessories compatibility?

[@whatskenmaking]

I suppose I could’ve give a bit more info about what when into those remarks! I rated it as ‘good’ because of the USB-A and the USB-C connector. Everything works, but it’s not as clean and requires some additional considerations

[@Brux-_-304]

Have you dumped the flash from the DE10 and compared it to the MiSTer Pi flash? It may just be a straight clone

[@whatskenmaking]

No, but that's a good point. I would expect it to be empty... unless the HPS is caching the bitstream through the chip. I'll check into it when I get a chance.

[@prufrockrenegade]

This was my first thought as well

[@willuigi64]

10:03 This board had an issue with latency on previous n64 cores upon the board’s release. Robert FPGAzumSpass, the core developer, saw that it was an issue with the core’s clock offset (when it was looking for data from the ram chips) and corrected it. It was inconsistent depending on the ram addon boards as well, so I do believe there may have been some sort of issue due to the onboard Micron chips. I believe I was the first to speak of the issue on the MiSTer FPGA Discord, and I’ve had my Retro Remake MiSTer Pi board for a while now. It performs great in PSX, Neo Geo CD, Saturn, etc, and after the update from Robert, N64.

[@whatskenmaking]

Yeah, I did some research into that problem based on Robert's explanation and was glad to see that it was easily fixed. It looked like it was related to the SDRAM rather than the onboard DDR, so that's why I didn't mention it there.

[@willuigi64]

@@whatskenmaking It was odd. It appeared to be an issue with the Retro Remake issued SDRAM, but people tested problem RR SDRAM on Terasic DE-10 Nano and the core ran fine. So I thought maybe some tolerance on the board along with the RAM was cause for issue. It could go either way. Either way, we don't exactly need a real result if the core was fixed to account for it and everything else is running fine.

[@grumpyoldgamerUK]

The same issue affected the QMtech board too or at least mine with the soldered on SDram The theory is it's due to trace length and single integrity due to both Taki and QMtech using their own PCB designs. Robert stated the core was set on the edge anyway which was fine for the DE10 and hence why a simple adjustment fixed it for both Taki and QMtech I have been testing my QMtech stack for a couple of months now and apart from the N64 issue it works just as well as my DE10 build

[@thebrigandier]

The chip with unknown data is spooky.

[@ganswijk]

I have a second original DE-10 Nano, I got by mistake (but paid for). Anyone interested?

[@iamdmc]

why would anyone bother with a 12V PD when it causes more problems and the board runs off 5V anyway?

[@whatskenmaking]

The one advantage is that you can get higher power throughput with 12v because it will support up to 36W, whereas the 5v will only do 15W. But even if you attach 8 USB devices and they all use 500mA (the max for USB 2.0), you're still going to be well under the 15W maximum because the MPI does a good job on power efficiency. Maybe SNAC usage would break that though - I don't know if there are any current limits through the SNAC port.

[@iamdmc]

@@whatskenmaking 36W is way overkill for a mister imho

[@whatskenmaking]

Yeah, I can’t imagine many reasonable setups that would exceed 15W

[@iamdmc]

@@whatskenmaking I just bought a Mister Pi turbo kit based on your recommendation :) got it at half off using Taki's promo code (I basically won a contest by guessing the promo code correctly based on his video hints)

[@thaKingRocka]

Is it just the 5v that makes the difference in the heat on that converter? Would a 5v 4a produce significantly different results from a 5v 2a PSU?

[@jstro-hobbytech]

haha i was gonna say looks like an eprom or the like. i've got a super expensive logic analyzer that i've yet to use, got it free. i regret buying such an expensive scope when i shouldve bought an older tek mdo with spectrum analyzer. i saved up for a siglent sa last month but bought a new guitar instead haha. whats the point of the mister ken? i have hard drives full of games that i can just line out to my oled. is it for scaling or something or just the convenience of the size? i got rid of my retro collection years ago. i regret giving away skies of arcadia the most and i had hundreds of snes games and other weird stuff. it became an obsession and i find if you collect too much of one thing the collection tends to own you and occupies way too much mindshare i have lots of little collections now though so it's the same i guess. haha

[@yoppindia]

why is de10 nano so expensive, they should have cut their prices, but don't seem to be doing it.

[@kohl1999]

It is great Taki is doing this, I just wish there was reasonable availability of the MiSTer Pi :( The first two batches sold out in seconds, and the follow up batch seems to have been delayed a bit. I was actually able to pick up a QMTech MiSTer and love it. High quality and very affordable.

[@whatskenmaking]

Agreed! I would love to have one myself for further testing, but the QMTech board has been my 'daily driver' for the past couple of months.

[@gammaphonic]

It’s the first product release from a brand new company. I don’t think it’s fair to expect a limitless stock availability in that circumstance. I’ll bet in a few months time they’ll be readily available for anyone who wants one.

[@whatskenmaking]

Agreed - it's the ongoing challenge with smaller companies building good products

[@kohl1999]

​@@gammaphonic Right, and I don't think anyone expects Taki to sell batches of 10,000 units. I applaud the guy for putting forth the effort and time to put the kit together and give the option. I also know he is working on the portable stuff so he has to divvy up his time accordingly.

[@ninetendopesaitama2107]

It's micro usb not mini usb. ☮️

[@jackipiegg]

24:57 Wait, wtf is that?!

[@whatskenmaking]

That’s the DIY MiSTer Handheld… next video 😁

[@jackipiegg]

@@whatskenmaking Is it a 4:3 screen?

[@whatskenmaking]

no, 16:9

[@appliedengineering4001]

To answer your question @ 10:22 in the video. That 8 pin ROM chip is were the FPGA's programming/configuration data is stored. Upon power up, the FPGA reads that chip and load the contents into the volatile wiring memory of the FPGA chip.

[@whatskenmaking]

That's true for some configurations, where the flash chip is used to store the bitstream. But for the MiSTer, the bitstream is loaded from microSD through the HPS. I don't know if it caches in the flash chip, but given that the chip isn't on the QMTech board, I would assume that it doesn't. It makes sense to have it in an FPGA dev board for the reason you stated, but it's not necessary for a MiSTer

[@Overdose140]

⁠@@whatskenmakingwhy assume people will not just use the Mister Pi as a cheap alternative to the DS-10 as a development board?

[@jj74qformerlyjailbreak3]

I now know whats in your 64mb flash chip. Wanta know??? Data. 😂

[@whatskenmaking]

🤣

[@Psilobite]

If you can't even buy it because it's always sold out, what's the point?

[@RetroRockGamer]

Why oh why does your DIY handheld use a widescreen screen? Everything that the mister plays is 4:3...😢

[@whatskenmaking]

I'm with you - I'd love to make a 4:3 handheld. Unfortunately, they're hard to find, and when you do find them, they're typically analog. The 16:9 screen is just easier to use and the particular screen I used is powered off 5v and easy to tap into audio. Heber made a cool magnetic bezel to convert 16:9 into 4:3, so maybe someone can add that to the DIY handheld when I release the Github (soon!)

[@_specialneeds]

The qmtech board with built in SD RAM is far superior.

[@mjc0961]

Of course the plagiarism machine known as Chat GPT was useless for figuring out what the code was. I wish you would have had more respect for all of our time and not included a segment that ended with "I got no answers from a useless AI chatbot." All it needed to be was "I dumped the chip but couldn't figure out what the code is for, so I uploaded it for others to look at" and then move swiftly on.

[@jakubknotek4891]

Send a refund request for a minute of your life lol 😅

[@macgeek21]

did you forget about the taki udon?

[@whatskenmaking]

How so?

[@Genesjss]

This IS the Taki Udon board he's reviewing.

[@mamaharumi]

Taki sucks, and the name is lame as hell, but it's still a cool concept.

[@Brux-_-304]

What’s Taki suck for? I’m genuinely asking. I’ve only seen his stuff pop up on KZbin every now and again. I think I missed something.

[@bruce_just_]

cool story - now show me on this Internet doll where Taki hurt your feelings.

[@MozTS]

Stop giving money to this taki scam artist

[@kohl1999]

I am very curious, why do you think Taki is a scammer?

[@Brux-_-304]

@@kohl1999me too. I keep hearing people say bad stuff about Taki but no one ever has an actual information to back it up.

[@MegaDeKay]

Haters gotta hate