[hpsdr] DSP chips

[Howard Long]

Hi Phil

> Are there any 32 bit DSP chips from either TI or 
> Analog that has free development tools?

ADI Blackfin has a GNU tool chain. I have never used them, although when
choosing the devices for use in the AMSAT-UK SDX over here in Europe about
1.5 years back I took note of the maturity of tools when making the
decision. At that stage I did not feel that the Blackfin GNU tools, in
particular gdb, were mature enough.

The dev tools that come with the $399 TI 6713 DSK will produce code for
other non-DSK platforms but the IDE (and thus the debugger) is tied to the
DSK board integrated USB JTAG and will not work with any other JTAG
emulators. If you want to debug without the DSK sadly you need the uber
expensive Code Composer Studio dev tools. At the time, I felt that we could
build a cut down DSK and fly that, although things have rather moved on
since then!

You can make the TMS320VC33 DSK tools compile code too for non-DSK
applications.

The 672x devices now slated for use on the SDX are pretty similar to the
6713, but the on chip peripherals are different, some very different, like
the DMA.

At a TI course I attended earlier this year there was a brief talk about GNU
tools for the TI devices, but I am sure it's nowhere near as advanced as
that with the Blackfin device.

Among other decision making axioms was that for our project we wanted a
floating point CPU and the Blackfin is fixed point.

In general, for the SDX project the algorithm code is developed on the PC
first using a soundcard and then it's ported to the TI device using a
different "HAL" library. Of course, at the hardware layer everything is
different, but the algorithm code is identical execept that we occasionally
poke in a conditional compilation to take advantage of DSP specific explicit
instructions (eg, high precision divides and square roots on DSPs in general
are not at all time efficient).

By the way, this is the AMSAT-UK prototype SDX.
http://www.g6lvb.com/img_1814.jpg and
http://www.g6lvb.com/eseosdx.tif 

73, Howard G6LVB


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