[sdiy] Speaking of dsPIC microcontrollers...

[Mikko Helin]

Hi list,

Speaking of choices has anybody tried TI's C2000 series "32-bit
Real-Time MCU's" yet?  Latest Piccolo models like F28069 have floating
point support which in threory could  make them easier to use - just
convert your Matlab code to C / C++ and you're done. Precision is only
single but nevertheless interesting. It's got one McBSP port so I2S
CODEC's can also be used. They are cheap, but some JTAG programmer
like XDS100 is needed and will cost extra. Available in 80-pin LPQF so
it's DIYable, too.

Another and very different CPU is XMOS XS1-L1 - it's like half FPGA
and half MCU. No peripherals either. Software I2S available. Found one
synthesizer type project from xmoslinkers forum, might be a good
starting point:

 http://archive.xmoslinkers.org/node/122

 - Mikko


>> To: synth-diy at dropmix.xs4all.nl,
>> From: Eric Brombaugh ebrombaugh1 at cox.net,
>> cc:
>> Subject: Re: [sdiy] Speaking of dsPIC microcontrollers...
>> Date: Wed, 22 Dec 2010 10:11:40 -0700
>>
>> ________________________________
>> On 12/22/2010 09:51 AM, Paul Maddox wrote:
>>
>> > It's interesting to see what devices people pick to use for their
>> > projects, it'd be nice to understand why they make their choices.
>>
>> I've tried a lot of processors over the last few years - dsPIC, ARM7,
>> ARM9, DSP56k, TMS320XXX, MIPS, etc. I'm still using dsPIC though. Reasons:
>>
>> * Inexpensive ($5 - $10 in small qty)
>> * Wide variety of pinouts, packages to suit different types of development.
>> * Nice instruction set, lots of gen. purpose registers
>> * Lots of docs, libraries & examples
>> * Good peripherals (DMA, SPI, I2C, Codec ifc, DAC, etc)
>> * True DSP (MAC with dual parallel operand prefetch & address updates)
>> * Reasonably fast, single-cycle instructions, no wait states for RAM,
>> Flash at full speed.
>> * Decent IDE, C compiler is free (with limitations)
>> * Inertia - I already know it.
>>
>> There are a few things I don't like too:
>>
>> * Power diss a bit high at max clock rates
>> * Documentation can be a bit cryptic
>> * 16-bit math limits some functions, double-precision slows things down.
>> * Limited on-chip RAM & no simple/fast external mem expansion
>> * No USB peripheral
>> * Max clock rates a bit low compared to some DSPs
>> * No up-to-date OSS/Free dev tools
>>
>> Overall the upside outweighs the downside for me. I've done more than a
>> dozen projects with this processor family and except for systems with
>> extreme requirements I'm not likely to change in the near future.
>>
>> Eric
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