Time was when chip makers’ processor evaluation boards were well beyond the reach of ordinary mortals. That didn’t matter, of course: ordinary mortals weren’t interested in small, nude motherboards designed to help designers of embedded systems judge a microprocessor’s suitability for the application they were working on.
Then, in rapid succession, came Arduino, Beagleboard and Raspberry Pi, and suddenly wee, bare and now cheap motherboards were all the rage. Arduino emerged as a great low-cost controller for hobby electronics. The Pi has the loftier goal of teaching the world to code. Despite its size, it’s more sophisticated than the Arduino: a desktop computer, essentially. The Beagleboard’s successor, the Beaglebone, sits between the two.
One interesting thing about the Pi and the Beagles is that they’re essentially old-style evaluation boards, for Broadcom and Texas Instruments chips, respectively. And here comes another: MIPS’ Creator CI20. MIPS, once a popular maker of Risc CPUs for Unix workstations, is now a subsidiary of Imagination Technologies. Just as Imagination founded Pure to make digital radios to show off Imagination’s DAB chips, here’s the CI20 to show off MIPS processor tech and Imagination’s PowerVR GPU.
Unix workstations having been out-evolved by Intel chippery, MIPS today has its gaze fixed on the embedded world, where it competes with ARM instead. It has had some success: Imagination will happily tell you that MIPS chips can be found in three billion-odd devices. The problem is, they’re not the sexy ones. While ARM is in smartphones and tablets, you’re more likel to find a MIPS chip in a home wireless router or a bit of telecoms infrastructure. Important for sure, but not something to wow ‘the kids’.
Which is where the CI20 comes in. If World+Dog expects evaluation boards to be as cheap as the Raspberry Pi, then here’s a low-cost MIPS-based board. Professionals assessing the MIPS-based Ingenic JZ4780 SoC for a new set-top box or carrier-grade networking box would buy one anyway, but at £50 the CI20 is now an alternative to the like of Pi and might just start winning for MIPS a fresh audience of enthusiastic youngsters.
So, as a techie keen to get closer to the metal, should you consider this figment of Imagination? On paper, the CI20 is an intriguing prospect. The China-made JZ4780 contains a pair of 1.2GHz 32-bit MIPS cores and a PowerVR SGX540 – by no means a feeble GPU. The board has 1GB of DDR-3 RAM and 8GB of Flash storage with an full-size SD Card slot if you need more. Having only two full-size USB (2.0) ports may seem ungenerous, but it’s enough for a keyboard and mouse. WiFi and Bluetooth are built in, so you won’t be adding dongles for wireless connectivity. There’s an RJ45 jack for 10/100Mbps Ethernet.
When Imagination first began talking about the CI20, early last Summer, all that made for a compelling alternative to the Raspberry Pi Model B. Since then, however, we’ve seen the arrival of first the B+, which addressed its predecessors quirks, most notably the paucity of USB ports, and now the Pi 2. The freshly blown Raspberry sports a 1GHz quad-core ARM Cortex-A7 CPU and 1GB of memory. But even the new Pi lacks on board storage and a real-time clock – the CI20 has both.
Comparisons between the CI20 and the Pi are justified because that’s clearly what Imagination has in mind. If the try-to-beat-Pi spec wasn’t sufficient to convince you of that, how about the fact that the CI20 not only exposes its SoC’s GPIO pins and multiplexes in the usual standard buses – UART, SPI and I²C – but also arranges them in exactly the same way the original Pi does? With 3V3 and 5V0 power feeds and 3V3 logic, that puts the CI20 right in the Pi’s tin.
Both products use HDMI for output and have tiny camera connectors. The CI20 also has a third, mini USB port for on-the-go, extra GPIO on a secondary bank of pins and a dedicated UART header. It uses a standard barrel connector for power – a USB-to-barrel cable comes bundled. That, and the 8GB of Flash pre-loaded with Debian, makes the CI20 ready run – not the case with a raw Pi, for which you need cables and a memory card.
The Pi’s strength, however, is not its out-of-box experience but its emphasis on access for non-techies. The Raspberry Pi Foundation put in a lot of work making the Pi’s hardware features, in particular the GPIO, accessible from Python. The Pi’s version of Debian, Raspbian, has all the appropriate drivers installed in the kernel and middleware in place to tie everything together.
No so the CI20. I intended to bring over a little Python code to run the inevitable ‘Hello World’ to flash an LED, but the CI20 has nothing like the handy
RPi.GPIO module, so I had to hack it up using a bash script and Linux’s
sysfs interface. Imagination seems to expect we’ll all be writing CI20 applications in C, but if it hopes to get hobbyists knocking up Internet of Things gadgets based on its board, it will need to make its platform work with friendlier languages.
And more complete. I thought I’d try some I²C peripherals, but despite the bus being notionally accessible through the GPIO pins, it was unavailable. There was no kernel module to load, no
/dev/i2c*. So you may be compiling new kernels if you need to get down to that kind of level.
Unlike the Pi, there’s no real community behind the CI20 yet. I’m sure the board has its fans, and they’ll be publishing blog posts with how-tos in due course, but there’s very little there yet. Given the CI20’s early unfriendliness toward anyone who isn’t among its classic evaluation board audience, I can’t see the Imagination offering reaching the kind of audience the Pi enjoys for quite some time. And as has always been the case, these things feedback on themselves: the more community members, the more active the community and the more new folk – accessories and add-ons too, for that matter – are attracted to it.
Then there’s general performance. After an oddly long-seeming pregnant pause, the CI20 boots quickly but straight into the Xfce desktop. Speed-wise, it’s a dog. So is the old Pi’s desktop, of course, if you’re used to the GUI performance of a ‘full’ computer. It’s like wading in treacle: windows don’t appear immediately and there’s much tearing as windows are moved, often dragging intermediate renderings around with them when they pass across other windows. This is a surprise given there’s a reasonable GPU in there and, more to the point, the board’s developer owns the GPU source code. Presumably, Imagination doesn’t want to open it, which is why is graphics demos, though launched from the desktop, appear to be rendered in some other, non-Linux space.
Of course, many CI20 users will go straight the command line anyway, but it would have been nice to be able to use the GUI. Running the Quake III Arena-derived OpenArena, you can have a playable game, but only just. Lots of frames get dropped, often when you’re trying to sidestep that rocket bearing down on you.
Other OS choices include Android, Arch and OpenWRT, and the excellent media centre OS, OpenElec, is coming too. If it can make use of the SoC’s HD video decoder, the CI20 may very well make a rather good media player. That said, I tried OpenElec, but not successfully: it wouldn’t compile for the MIPS architecture, and will take a lot of digging around for undocumented files in GitHub to fix the problem. So I tried Kodi aka XBMC, the very popular media centre app (OpenElec = Linux + XBMC/Kodi) which, with a bit of jiggery-pokery, I got to install and run. Alas, the three 1080p HD, 720p HD and SD MP4 files I tried all crashed it. Not much info in the system log to say why, so I tried turning off hardware acceleration in case that wasn’t supported somehow, but it made no difference.
You’re probably not going to get a handy case for the big, square-ish CI20 board, or much in the way of advice from expert users in the community. The CI20, despite its comparable spec, price and Raspberry GPIO-friendly layout, is no Pi. You can drop Pi add-ons onto its GPIO pins, but you’ll have to put a lot of effort into getting them working. That’s work is done for you in Pi-land. The CI20 has more hardware features than its rival, but for me they don’t outweigh the broader benefits the Pi’s community brings it. Maybe – hopefully – that’ll change, but I can’t rid myself of the notion that, beyond a professional userbase, the CI20 is going to be a minority interest for some time. An interesting entré into the world of MIPS, yes, but that’s really it.
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