Raspberry Pi + Arduino Shields + BBB Cape + FPGA to hook them all up

[miguelvp]

If you are still thinking about having a Max based option in parallel development, they just announced the Max 10 series and they are calling them non-volitale FPGAs:

http://www.altera.com/devices/fpga/max-10/max-10-index.html?utm_source=altera&utm_medium=newsletter&utm_campaign=inside_edge

No idea how many LE's they will have but they do talk about NiosII soft core

Also:

MAX 10 FPGAs are built on TSMC’s 55 nm embedded flash technology enabling instant-on configuration so users can quickly control power-up or initialization of other components in the system. The devices also include full-featured FPGA capabilities such as digital signal processing, analog functionality, Nios II embedded processor support and memory controllers.

Edit: No idea on how long to market, but I know you probably have an idea on how long it takes them to get things to market

[rob77]

what software will you provide for the Pex ?
APIs for all involved platforms will be needed to ensure success of your project. i would not recommend to start the kickstarter campaign before you offer the software APIs.

btw.. i've checked the LOGI-pI and LOGI-Bone - those make sense to me - small & compact , providing a learning platform for FPGAs and allows you to  use the already available peripherals (arduino shields, and Pmods compatible boards), and of course they have software APIs available.

actually the small & compact is a killer feature - it gives you the possibility to use it even in the "final" product. - from the business point of view - much bigger target group.

[thinlayer]

The API structure is being desigened. Right now:
1. functions/APIs to write to the FPGA over I2C and set registers.
2. The registers will be control the destination of each of the 17 IO pins.
3. So the SPI can be routed to wings 1, 2, 3, or just 1, or 1, 2, etc, same with all peripherals
4. Use regular SPI, I2C, GPIO code to keep backward compatibility with existing developments.

Logi-Pi is a good product and I can't carbon copy it. I know Michael and he's a good guy. We're talking about working on drivers together and perhaps a hardware development once he's freed up. I want people to buy his product if they think it's perfect, and I'm trying to do something different.

One difference is I'm keeping connectors on the top side though, because if I make the board top + bottom it doubles the packaging thickness. If I keep the parcel under 20mm I can use international letter post which is *cheap*. This will also allow you to lay the boardset flat behind an LCD.

Talking to a few China board stuffers now, waiting on some indicative prices that will be critical to the KS.

[rob77]

ok. that's the "hardware" API. but you should provide software API as well - bindings for Python for the Rpi guys, libraries for the Arduino Guys...etc..

you will have to provide those in order to have a successful project and a backed KS campaign.

[thinlayer]

This is probably my downfall. I haven't got a lot of experience coding on RasPi, so I'll delay until I've sized up the library task and learned a bit more about developing in Pi. 

[thinlayer]

One other thing... Is there much point:

a) Driving an LCD from the FPGA?

The Pi's DSI interface is about to get DSIPy. http://raspi.tv/2014/raspberry-pi-official-7-inch-dsi-prototype-preview. This will shi1t all over anything I can do through the SPI/P1 pins. Just not enought bandwidth. To do any image processing I'd have to put a HDMI decoder or worse, a MIPI-DSI decoder chip on the product and - whamo - there goes <$100. So if anyone wants to have video processing; that's a custom board and another project (that I would love to do, video processing is my thing, but I'm not sure it's a huge market for Pi people.)

b) Putting any LVDS access on the PeX

LVDS is good for two things I think: 1) driving LCD, now a moot point, and 2) high BW link between two chips. So my goal is to give Pi users access to hardware that wasn't targeted to the Pi, then what hardware is there out there that is affordable and has an LVDS interface? I'm not sure I know of any.

Call for collaborators

BTW if anyone wants to collaborate on this I'd love the help. I lack real domain experience in Raspberry Pi and believe other people out there would be more effective getting the Pi side API and framework together. I'm making PeX open source hardware and the Kickstarter project (if successful) would cover cost of manufacture so long as we don't fu$k it up. I will prototype out of my own pocket and have most the BOM on hand already anyhow.

I would really love someone to help with Software Development, heavy lifting on the Kickstarter page and marketing in return for a share of whats left over at the end. The worst we could get is good karma and reputation points.

[miguelvp]

Looks cool but: 800 x 480 pixels might not make it too appealing, you can do better than that and drive a 1920x1200 WUXGA display (supplying the frame buffer for that, might be a problem at 6.6 MB).

But you can always have a lower  resolution frame buffer 960 x 600 under 2 MB. and a 1920 vector buffer for say displaying waveforms. But I don't know how hardware driven are the Pi followers.

As an input it will allow you to capture high speed signals, like an ultra fast logic analyzer.

With a resistor network you can make it TMDS compliant. and vice versa.
Here is a nice paper about interfacing LVDS:
http://m.eet.com/media/1135468/330072.pdf

LVDS will also gives you Ethernet, mute point as well because the Pi has Ethernet, unless you want to do your own hardware layer protocol but I can't see Pi people doing that.

Other uses but not achievable as far as I can see:

Camera Link uses LVDS but those cameras are way too expensive, normally used for commercial machine vision

Serial ATA. But even to achieve SATA 1.0 at 1.5 GBits/s might be a stretch for the FPGA to switch at two thirds (0.6666) of nanosecond.

PCI express uses it too but that will require a lot of FPGA i/o pins even for 1X, and now we are talking about a 2.5GHz clock.

I would love to help but even if I have a Pi (got it for Xmas from my son) I have yet to use it for anything (I did set it up for XBMC and got it running but just to make my son happy) I will eventually use it but I have not looked into it much.

[thinlayer]

That's a great article thanks! 

I wasn't aware that a resistor conversion could work. I've seen TMDS decoded on Spartan-6 parts before, but I had assumed that the IO of a Spartan-6 was tailored to TMDS. I will take a long look and see if a HDMI connector could find it's way onto the design for another $5. Certainly it'd be a strong feature, and I could mount a Hirose DF13 connector for a laptop screen, and make a backlight driver shield to drive anything up to 15" quite easily for about $30 resell. This would suit a Cyclone V with some DDR3 running at 333MHz/400MHz, and there's plenty you can do with Machine Vision, object recognition, edge detection, etc. All good fun with the RasPi's camera board.

PCIe is achievable using a 'GX' part FPGA with inbuild gigabit transcievers, and an 'F' Cyclone V variant with built in PCIe endpoint hardware; but a GX part has fewer IO, memory and DSP resources than a standard Cyclone V 'E' FGPA $ for $ but there is no IP cost. Still, I would expect it wouldn't be well utilized by Pi people. SATA same story - use a GX but then the IP gets 3rd party expensive. I think SD card peripheral is best I can offer here. Ethernet on an FPGA is a farce, they are for ultra high end networking apps only. Forget about it - buy the MAC, buy the Stack, mount the Phy chip.... $$$. LWIP is free but a sizable software challange. Give me a Wiznet 5200 for simple ethernetworking on FPGA, and it's already there on the Arduino Ethernet sheild.

I'm hoping to take some photo's of concept #2 later today that I'll post.

[Rasz]

One other thing... Is there much point:

a) Driving an LCD from the FPGA?

The Pi's DSI interface is about to get DSIPy. http://raspi.tv/2014/raspberry-pi-official-7-inch-dsi-prototype-preview. This will shi1t all over anything I can do through the SPI/P1 pins. Just not enought bandwidth. To do any image processing I'd have to put a HDMI decoder or worse, a MIPI-DSI decoder chip on the product and - whamo - there goes <$100. So if anyone wants to have video processing; that's a custom board and another project (that I would love to do, video processing is my thing, but I'm not sure it's a huge market for Pi people.)

Foundation has been promising it for two years now, and showing off for a year. When it finally ships it will be locked down to ONE particular lcd, just like their camera driver works with only one particular sensor because "users are too stupid" (paraphrasing actual Broadcom engineer).

SII1161 (dvi receiver) is $3 on ebay
http://www.ebay.com/itm/50PCS-SII1161CTU-Manu-SILICON-Encapsulation-QFP-100-PanelLink-Receiver-/371080259705?pt=LH_DefaultDomain_0&hash=item56661b6879

http://www.skyvision.fi/screens/suojatut/WP2_DigitalVideoTransfer/Datasheets/1161_SiI-DS-0096-A.pdf


>HDMI connector could find it's way onto the design for another $5

!?!? hdmi socket is like $.4
http://www.ebay.com/itm/50pcs-HDMI-19Pin-SMT-Type-A-Female-4-Legs-Socket-Connector-HW-HD-011-/170711102220?pt=LH_DefaultDomain_0&hash=item27bf2cb30c


Additionally look up Mike Video diary on MIPI reverse engineering - FPGA can emulate official Pee Camera module (basically convert RGB from DVI slot to raw bayer/YCbCr /whatever its configured to send) and connect directly to Pee MIPI CSI slot = you get FULLHD DVI grabber that does hardware MPEG4 encoding on the fly. Pee can stream video from mipi camera with <100ms delay over the network - you instantly get a ready for use product. Even Dave could use one of those for his Tagano

Number of people that want to play with FPGA < number of people that will click buy when they see something USEFUL done with said FPGA platform as one of shipped demo projects.

[thinlayer]

SII1161 (dvi receiver) is $3 on ebay

Yes, but what happens if I get orders for 200pcs. I'm not sure hkutsource is a 'risk free' supply chain partner. Silicon Image are a company that doesn't have a channel for low volume customers and I can't buy direct; they service consumer market OEMs and measure orders in multiples of 10kpcs. These eBay and other traders are picking up the tail end of big orders at Foxconn and other CEMs in China and they are BAD news.

!?!? hdmi socket is like $.4

A chip like this is a better option but not cheap: http://www.digikey.com/product-detail/en/TMDS351PAG/296-21970-ND/1632634. @250pcs = $3.83. Now add the connector, and yes $0.4 so a $4.20 solution. Now extra development. Now testing. Now Yield. Now product returns. Now markup - The rule of thumb is 70%; so you see where I'm going? It's a line call when you are trying to get the price below $100.

Do it with passives and perhaps the numbers change in favor of inclusion but the jury is out on whether that would work or not. Altera have kindly donated me a Cyclone V GX kit and I'm going to cut some HDMI cables up tonight.

Additionally look up Mike Video diary on MIPI reverse engineering - FPGA can emulate official Pee Camera module (basically convert RGB from DVI slot to raw bayer/YCbCr /whatever its configured to send) and connect directly to Pee MIPI CSI slot = you get FULLHD DVI grabber that does hardware MPEG4 encoding on the fly.

Might be worth a look. I'll spend some time reading MIPI specs and watching the videos. Thanks.

[Rasz]

You are absolutely right about finicky nature of chinese ebay parts availability and provenance. Still doesnt hurt to ask them directly about  bigger orders. Then you also have agents specializing in shenzhen electronics. Ian from http://dangerousprototypes.com/ had a great tour recently with workshops, supply agents were one of the topics, video is on their YT channel somewhere with contact info for one of the agents.


I dont think you will be able to handle raw dvi 1080p @60 as its ~150mhz pixel clock = 1.5Gbps of serial data. Thats why its easier to just slap a decoder. Users could just set their pees to 1080p@30, thats only ~700Gbps, but that limits use scenarios.
Mipi is a little easier because it has four data lanes instead of dvi's three.
LVDS does two pixels per clock at fullhd so also no problem.

Can GX 3gbps transceiver be clocked externally? I glanced over pdfs and all I saw was automagic clock recovery.

You can make dvi decoder an additional perk/level in the campaign and provide it on separate pcb. As long as you have that wow/must have feature in your KS promo video it probably doesnt matter how its delivered. Pee connected to few differently sized LCDs recovered from broken laptops with big bold subtitles emphasising those were 'FREE LCDs you can get anywhere !!1' will do the trick.