The SX was/is a great chip. (I still use them on a near daily basis)
Troubled history, though. This is part of why Parallax developed the
Propeller.
The premise behind the propeller, is that it is based on the Virtual
Peripherals of the SX. You simulate peripherals by having interrupt code
On Thu, Jan 23, 2014 at 2:00 PM, Tom Van Baak t...@leapsecond.com wrote:
Has anyone else looked at the Parallax Propeller processor for timing
functions?
Hi Brian,
Oh yes. Really nice chip. But for precise timing applications I had huge
problems with phase and temperature stability of
Brian,
Well, my disciplining code is going to run as an FLL rather than
a PLL to generate the correction for the OCXO or the Rb reference.
The Propeller should work fine for a GPSDO. AFAIK no one has done this yet and
I encourage you to try. The Parallax Propeller chip gets mentioned on the
Given that Arduinos are now sold in (almost) every super-market, and the
programming IDE is free/open-source, and the C/C++ code is familiar to
many, I would have thought the logical evolution of the pictic is to
become an Arduino shield?
One drawback (AFAIK) is that e.g. Arduino Due doesn't have
It seems that that the QEI on a dsPIC are internal hardware counters
decoding the A/B phases of optical encoders: are you sure that they
can be used like a time interval counter? Better to use the timer
capture dedicated input.
On Thu, Jan 23, 2014 at 12:31 PM, Anders Wallin
measurement time-nuts@febo.com
Sent: Thursday, January 23, 2014 3:31 AM
Subject: Re: [time-nuts] PICPET- was Affordable (cheap) COTS (etc)
Given that Arduinos are now sold in (almost) every super-market, and the
programming IDE is free/open-source, and the C/C++ code is familiar to
many, I would
, January 23, 2014 7:24 AM
Subject: Re: [time-nuts] PICPET- was Affordable (cheap) COTS (etc)
It seems that that the QEI on a dsPIC are internal hardware counters
decoding the A/B phases of optical encoders: are you sure that they
can be used like a time interval counter? Better to use the timer
Has anyone else looked at the Parallax Propeller processor for timing
functions? It has 8 cooperative cores and has a number of intrinsic timing
functions for measuring intervals accurately, or for generating
tightly-timed repetitive pulse trains, within the frequency accuracy range
of the
As usual the hardware peripherals integrated in microprocessors are
not really independent from the core: the capture signal must be
synchronized with the microprocessor's clock to enter the core. This
require usually a clock with double the speed you need for a real
hardware counter implemented,
Has anyone else looked at the Parallax Propeller processor for timing
functions?
Hi Brian,
Oh yes. Really nice chip. But for precise timing applications I had huge
problems with phase and temperature stability of its internal PLL. I tried half
a dozen different boards purchased over several
Good thread.
Yes I am very aware of the parallax propeller. As you both say kind of a
crazy chip. I have used another product the SXB micros. They run Basic at
80 Mhz and are so cheap that If I have more than a few chips I just switch
over. Unfortunately they are obsolete in the dip form. When I
That´s a big problem. To go sub-100ns you must make frequency 10Mhz,
and most of these chips only run at 10MHz using internal PLLs (you
can´t directly clock them with more than about 20MHz.. or at least the
datasheet says so).
A FPGA has no such problems (or at least they are very
Tom,
Do you know of any other PIC projects that get a greater resolution? I was
thinking of doing something with a dsPIC33 running at 140MHz or greater, but
I'm not sure I want to devote the time to if it's it's been done.
Bob
From: Tom Van Baak (lab)
Hi Bob,
It's pretty easy to get a tiny PIC or AVR down to 50 ns, so to me the next
sweet spot would be 1 or 2 ns. A couple of us are trying. Contact me off-list
re the dsPIC33.
/tvb (i5s)
On Jan 22, 2014, at 5:53 PM, Bob Stewart b...@evoria.net wrote:
Tom,
Do you know of any other PIC
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