An Open Source Hardware Development Tool

LuxuryYacht writes "The PLAICE is an open source hardware and software project developing a powerful in-circuit development tool that combines in one device the features of a FLASH Programmer, Memory Emulator, and High Speed Multi-Channel Logic Analyzer. It runs uClinux. The logic analyzer features up to 200MHz sampling rates and up to 32 input channels. The logic analyzer Java client supports up to 200MHz sampling rates, user-controlled filtering operations, time line in diagrams, transfer rates, and user configurable drawing modes. The Java client supports access via almost any PC with a serial port and uses the RXTX serial library with support for 34 platforms including Linux, Windows, and Solaris. Java client plugins include an SPI and I2C bus protocol analyzer, conversion of timing analysis to state analysis, and post-processing functions."

Comments

That's nice

[tftp]

But logic analyzers are history. If you want to debug logic today you use ChipScope. That's not just because it is easier, but because breakout connectors (Mictor etc.) are expensive, large, and they disrupt the timing of the circuit.

As memory emulator this device may be useful sometimes, but many MCUs today come with internal RAM, and those that don't - they expect DDR2 speeds, and you can't emulate that.

This can be a full-featured Microblaze development system, though, with tons of samples. I think that's its best value. MicroBlaze was always poorly supported by Linux, as opposed to Nios (which Altera itself supports.) If we have, finally, a working [uc] Linux port to MB that alone is a great achievement. When I looked a year or two ago there was only one, non-functioning, port to a hardware that did not exist.

Re:That's nice

[tftp]

Since when? Well, for some designs (like yours) they are still useful, and I am glad that there is still someone out there who knows which end of the soldering iron to hold onto.

But in an industrial setting they are quickly replaced by JTAG-connected tools; ChipScope in particular (if you are a Xilinx slave) is great because it captures the signals into the local, very fast RAM, and then sends you the snapshot over a slower JTAG connection. The snapshot is true to what is really happening, and if you design a DDR controller (or faster) then just forget the external wires, they are useless at those speeds. And most of modern commercial designs push the devices to the limit. That's what makes standalone logic analyzers less appealing to a mass manufacturer. Logic analyzers in such conditions become tools of last resort, just like ICEs, where you have to spend a day just preparing your board for testing.

Myself, if I do not have an FPGA in between (and so ChipScope is not an option) then I just use an oscilloscope. I have a 4-channel, inexpensive Infiniium model, and 3 probes is the most I ever needed; staring at the schematic does the rest :-)

Re:That's nice

[LuxuryYacht]

The logic analyzer design is targeted at debugging logic outside of the FPGA and the board itself. ChipScope is supported by the board for debug of logic inside the onboard Spartan-3E FPGA.

The memory emulator is currently targeted at FLASH devices.

Re:That's nice

[Alioth]

There are plenty of embedded microprocessors around that do NOT expect DDR2 speeds. Many digital circuits simply don't need a 2GHz space heater and run just fine with a 2MHz Z80 or equivalent (indeed, the Z80 is still manufactured and popular in its 'classic' 40 pin DIL form. I have one on my work table that was manufactured less than 6 months ago). Many many products use chips of this sort of class.

Just because there's a clamour for ever faster (and hotter) chips in PCs and servers, it does not follow that the same is true of an embedded computer. If a 4MHz processor works for a particular application, there is absolutely no benefit in using something that 'expects DDR2'. Normal 70ns static RAM and flash chips are sold by the millions because they are cheap, electronically simple to interface, and low speed circuits are much cheaper and easier to lay out on a PCB. You don't need DDR2 on a weather station embedded computer or washing machine.

Many microcontrollers like the Atmega can interface with external memory (even though they have some internal flash and RAM).

This could eventually be important

[Anonymous Coward]

If Microsoft gets what it wants, it will be hard to get hardware that runs Linux. Well that's Microsoft's dream anyway. In order to protect precious DRM Microsoft has ordained that only 'bullet proof' hardware will be allowed to run in HD mode with Vista. Their spec even says that unencrypted signals must run only on inner layers of pc boards.

Being able to create Linux friendly hardware could, if Microsoft succeeds, be necessary if we are to have high performance video and audio.

This project is not alone as open source hardware. My current favorite is the Arduino board using an Atmel microcontroller. www.arduino.cc I am also playing with the Make controller that uses an Arm. www.makezine.com/controller

Re:RS-232?

[tftp]

I see that the board has Ethernet transceiver installed, and the connector. However the SoftTEMAC IP from Xilinx is not free, and because of that you can't use Ethernet. Virtex-4 (and 5) FPGAs have HardTEMAC which is not just free, it is a hard core in the FPGA, so it is ready to use, and it can do Gigabit Ethernet as well. Because of that I may question the wisdom of picking a S3 platform that is some $ cheaper than V4 but requires a $5,000 IP to do something really useful (Ethernet connectivity is not too much to ask for these days.) Or, alternatively, write your own [T]EMAC module, it's not impossible but you need to be a decent FPGA coder to even get started.

Not open source hardware...

[plasmoidia]

The hardware is not open source. Actually, the hardware is a Spartan-3E Starter Kit board. Nothing special there. What will be open source is the *firmware* (as well as the software running on top). Semantics aside, this should be an interesting project. This seems to be an attempt to build an entire system in an FPGA with open source firmware/software. As others have expressed, I am not sure how useful it will be as a logic analyzer, but perhaps this could be a start for more open source firmware projects.

Re:RS-232?

[jcgf]

Yeah, the only problem is those never work ;)