Another vote for the
Zturn, and a mention that there's now a '
lite' version as well which has a Zynq7007S (single-core ARM) but still manages 23k logic cells for the princely price of $69 (£51) or $75 (£56) for the 7010 version. You don't get the HDMI on the 'lite boards, but the add-on "cape" which supplies the connector is only $29 (£21).
At first I was ignoring the Zturn boards because they came shipped with an HDMI chip that it's impossible to get a data sheet for, and there was no other access to the HDMI port. To add insult to injury, the HDMI core they provided was proprietary and shut itself down after 30 minutes of operation...
Now, however, they provide a standard Xilinx VDMA design (presumably, I'm still waiting on the '020 version of the board to arrive) which sets up the SIL9002A chip and then treats it like an LCD video-out (pixel-clock, pixel-data, hsync, vsync,data-valid). This has no time-out.
For the money, the Zynq boards are pretty much on a par with the S7 boards (Arty etc.) and they throw in a dual-core high-speed ARM chip, and a hard-macro DDR3/4 driver (so you don't waste 30% of your brand-spanking-new Artix35T on the DDR driver). In fact if you say you want the basics of something you can make a single-board computer out of (USB, HDMI, ethernet, SPI etc.) the '020 Zturn board seems to win hands down to me - that's a huge step-up in logic-cells/luts ...
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Chip Cells BRAM DSP Board Cost From
Zynq-07 23k 50 66 $69+$29 myirtech.com
Zynq-10 28k 60 80 $75+$29 myirtech.com
Zynq-20 85k 140 220 $99 myirtech.com
Artix-35 33.3k 50 90 $99 digilentinc.com
(-DDR) 22k 50 90 $99
Spartan7-50 52.2k 75 120 $109 digilentinc.com
(-DDR) 42k 75 120 $109
No, I don't work for the company, but I've spent the last few days looking for which board to get as an Xmas present for my next project. The price/performance of the Zturn board is *really* hard to beat. I'm including digilent's boards because they're the cheapest I know of for the Artix/Spartan7 series. If there's cheaper I'm interested to find out.
On the plus side for the Zynq, you get access to the dual ARM cores, and all the peripherals that come with it (USB, ethernet, SPI, I2C, CAN, SD card, etc.) and Vivado isn't that bad an environment to develop in, even if it has its quirks...
Minor niggles on the Zturn:
- It would have been nice to have the USB/SD-card on the right or left sides, so the board could be mounted in a case at the rear and provide access to all the ports. As it stands it looks like my case-depth is pre-determined and the USB will be at the front instead.
- There's no audio on-board to speak of (buzzers don't count)
- None of the outputs are 5v-tolerant. One solution to that might be to put an STM32 connected by SPI (or let the FPGA be memory-mapped if you're feeling adventurous). Then you have N (depending on the part you choose) 5v-tolerant IO's.
At the end of the day though, if you're dropping $100 on a board, you'd be nuts to overlook the zynq - for the price you get a hell of a lot.
