Friday, February 04, 2005

Random electronics

Time flies when things go wrong. However, on a few good notes...

FPGA's
I've pretty much settled on trying to get Actel's ProASIC-3E starter board. List price for the lighter weight version is $250 (due in quantities 2Q 2005). What I do like about it is that it includes a Libero GOLD license, which is all I really want. That's worth twice the dev kit costs. They're highly rad tollerant, so good if I ever decide to send up high altitude balloon sensors. Just no dedicated hardware DSP features (Multipliers, MACs, etc). Still might be cheaper to implement myself given how cheap the chips supposedly are.

Now, second on the list is Lattice Semiconductor. Similar issues, but I like their low cost LatticeECP for DSP route (same or better hardware as the big Stratix and Virtex parts from the top vendors). IF I decide I need DSP that badly, I might chase them down. Too bad their expensive dev kit hardware and 6 month free trial don't really cut it for me. I don't want to drop 2K on something that I might use a handful of chips my entire hobby career. I hate it when my software expenses outweigh my hardware. I'll probably end up turning back to Xilinx's Spartan3 or Altera CycloneII eventually, given better "free" software (both support, licensing, and specialized IP availability) for complex hardware support (video DSP, etc). It's a balancing act.

Circuit Cellar Contest
Well, I got my Renesas contest hardware from CC. 32 bit CISC microcontroller with a CAN port. Should prove fun if I need higher hardware speeds for my work (probably only if I start doing on the fly IK calculations for robotics right now). Although samples are still available, the starter kit I got isn't.

Datalink
So, thinking about my upcoming vehicles has me plotting out datalinks. While my Nordic based RF-24G transcievers are good for burst (1Mb/s) low power communications, they're going to drop off after a 100 feet or so, even out in the open. Something new has come to my attention, though. The dev kits for Aerocomm are readily available online at Mouser. 900MHz and 80Kb/s isn't too bad, with decent range. Higher transmission speeds usually demands higher frequencies (due to channel limits imposed by the FCC), more power to get to the same range, and more complex hardware (both electrically and mechanically if it needs a steered antenna). I'd love to get a more complex DSSS system to reduce interference, but that takes more power and more importantly money. We'll see where I go from here.

Another option is finish getting my Ham license and go into the 10GHz range. 900MHz omni for commands, 10GHz transciever for 10Mbit data transfer. Might be fun. I'd rather build a radar around the 10GHz gunnplexer, though. Maybe with an FPGA rear end a dual mode unit would be feasible.

1 comment:

wittend said...

Nice blog - you write well.

I am a programmer by trade, and have no formal training in in EE, but I have found electronics fascinating since I was very young. I'm interested in many of the subjects you talk about.

I am curious about your interest in FPGAs - have you done any more in this area? I have an Actel ProASIC Plus eval board - the ProASIC-3E boards were having the usual 'production delays' when I got interested in these. Then I found I was more than a bit intimidated by logic design at this level. It is probably just a matter of taking things in small steps. I have been hoping that Actel would release a modestly priced (<$350) 'eval' board for their new line with the ARM7 core - that would give me some more familiar landmarks. But maybe I dream...

Are you familiar with the FPGA4fun site at http://www.fpga4fun.com/ ? He has a small 100 MHz scope design with versions for either an Altera chip or an Xilinx - and everybody is giving away some version of their Dev tools now. I like some of his I2C widgits as well. He seems to be a good designer, though he is not quite as open about some things as the SparkFun folks. There are some good tutorials too.

-- Dave