Folknology wrote:2) Hardware - Ok its time to build my 1st Xmos board lets look at the obstacles thrown in my newbie path: Packages, damm it nothing through hole only surface mount bugger OK smd it will have to be. What are the packages ? G4 BGA ouch not a cats chance of me doing that, L2 WTF double row QFN and minimum 4 layer board lets forget that option what are we left with? L1-128 pin OK looking better, hold on 0.4mm pin spacing dammit can't use my low cost prototyping services then & how did they choose the pins using a dartboard? Lets try the next package L1-64 Ok that looks more reasonable ah oh see a bit of a problem it has a ground paddle that limits me to stencil and hot plate or perhaps more specialised kit like heat pencil grr. Ok lets assume I can somehow overcome the paddle thing (I'll convert my toaster oven) and lay it out. Dammit needing all of these decoupling caps around the L1-64 makes it near impossible to escape the signals without moving to tiny vias and track spacings, thats blown out my cheapo prototyping PCB suppliers again. OK one last go L1 48pin OK its got a paddle same issue as the 64 pin but I may be able to get around that using some hacking techniques and a hole in it. wow there still a lot of decoupling caps but I may just be able to get the signals out, better than the 64pin that's for sure. Right what else do I need? Flash Oh really doesn't it have any built in I thought it was an MCU? so lets add a flash chip and another decoupling cap, bugger I just lost pins, oh only 16 single bit pins? but can't I use them all as single bits? so now down to just 12 single bit pins then.. anything else I should know about? Dual power supply, Oh 1V for the core and 3v3 for the IO, so I need 2 regulators, what they should be switch mode? I'm a newbie I tend to use linear LDOs if pushed, anyone provide me with a decent circuit for the power supply side? Wow Xmos sure use a lot of different PSU chips, looks like every board and kit is different, I'll just randomly pick one and copy it.. Ok I'm done then?Oh of course I nearly forgot the clock I'll just add a cheap resonator, Oh no examples, how about a crystal hmm have to built my own external pierce oscillator WTF why can't I just add a crystal like other MCUs and what is one of them anyhow. OK so I have to add one of those teeny tiny 2 gate inverter chip that's near impossible to solder by hand with the crystal, surely I'm done now.. ? Power supply monitoring and power up sequencing what the hell is all of that? so two more teeny tiny chips that I haven't a clue about. Right I also need a boot loader nothing clever like JTAG programming, Xmos supports USB so I will use that. Oh I have to add a USB chip I thought Xmos was fast enough IO for basic USB, Oh its a tiny qfn chip Oh what joy as if my boards isn't difficult enough, well I will just have to convert that toaster oven then. Right now I'm ready to rock, what no virtual com port over USB but what about my printf debug? no programmable bootloader support your joking. That's not the worse bit OK let me have the bad news, Really my pins have been used up because of the spi flash and USB AARGHHHHH OK I give up I'm going back to my Arduino
Yup, I'm on the same boat. I have a XC1A kit for ages now, but couldn't make anything with it yet, and I'm always going back to my Arduino projects. I even managed to release Beat707.com, which is an Arduino project, and now I want to make it Xmos based, but I'm having all sorts of problems. But, again, I'm no expert, I'm just a crazy noob who wants to finish a project...
One thing that is really missing is a barebones PCB with just a dual-core chip, not the single ones, but the ultra power dual-core ones. Single core would be nice too, but there's already some ARM processors out there that are nice, cheap and easy to setup. NXP is another one that comes to mind. I can get a board on eBay for $ 28 USD that runs at 100 Mhz and is all ready to upload code via USB.
I'm thinking on a project that boots the XMOS chip from an Arduino, but I think its not possible, and wouldn't work, but I still think it would be great to get some Arduino users into the XMOS world, that would help the community a lot. But, what do I know?
Best Regards, WilliamK