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<div class="moz-cite-prefix">Since Raspberry Pi finally became
available, I've moved away from an STM32F4 attempt. There's not
much purpose to it.<br>
<br>
Raspberry takes some getting used to, I'm not very familiar with
Linux. The Debian Squeeze release that was out when Pi was
released became obsolete in mid-July with the much faster,
friendlier Debian Wheezy release. This is important because
Wheezy uses the Pi's hardware FPU, Squeeze did not, which is why
it was so slow. RTKLIB needs that FPU.<br>
<br>
I was delighted to find that Debian readily recognized the Silabs
CP2102 USB-to-serial bridge and even the uBlox GPS's USB port.
And on the GPIO pins, it also has a serial port there which is
supported by the OS. <br>
<br>
RTKRCV does compile with the GCC included in the Debian release.
However, I'm a bit unclear on how to configure the setup (calling
one GPS a static base station, for example), pass it the ports and
what sort of messages I can expect out of it. There's not going
to be any way to run the GUI version, I assume? Windows emulators
like Wine will never run on the Pi.<br>
<br>
Danny<br>
<br>
On 8/14/2012 2:35 AM, Michele Bavaro wrote:<br>
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<div class="moz-cite-prefix">Hello Danny,<br>
<br>
Have you done any real progress with STM32F4 then?<br>
<br>
Best regards,<br>
Michele<br>
<br>
<br>
<br>
On 03/05/2012 14:45, Danny Miller wrote:<br>
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<blockquote cite="mid:4FA27DF9.5050200@austin.rr.com" type="cite">
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I remember seeing that a long time ago, but forgot about it.
Hmm, it does have useful figures.<br>
<br>
The A8 at 600MHz would be capable of 1200 DMIPS. At 20%
utilization for 10Hz GPS operation that would indicate 240 DMIPS
used, and that's with the TMS320C64x DSP. However, AFAIK that's
not a floating-point DSP core and I expect you'd have to do a
lot of tinkering with the compiler to get it to send any math to
the DSP core. I suspect it wasn't used. The article doesn't
mention the TMS320C64x DSP except in the Beagle specs.<br>
<br>
The STM32F4 is capable of 210 DMIPs. Hmm, that's troubling.
There's still overhead which hasn't even come into play yet. I
would expect compiling to metal would be substantially more
efficient but I don't KNOW that.<span style="color: rgb(34, 34,
34); font-family: arial, sans-serif; font-style: normal;
font-variant: normal; font-weight: normal; letter-spacing:
normal; line-height: 16px; orphans: 2; text-align:
-webkit-auto; text-indent: 0px; text-transform: none;
white-space: normal; widows: 2; word-spacing: 0px;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; background-color: rgb(255, 255, 255); font-size: small;
display: inline !important; float: none; "><span
class="Apple-converted-space"></span></span> Then again, it
doesn't HAVE to be 10Hz, we could go with 5Hz operation, there's
no law saying it has to be 10Hz. Plenty of overhead at that
speed.<br>
<br>
Danny<br>
<br>
On 5/3/2012 1:04 AM, Michele Bavaro wrote:
<blockquote cite="mid:4FA21FE6.1020804@yahoo.co.uk" type="cite">Dear
Danny, <br>
<br>
Sorry, I assumed that you read this paper <br>
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="http://gpspp.sakura.ne.jp/paper2005/isgps_2009_rtklib_revA.pdf">http://gpspp.sakura.ne.jp/paper2005/isgps_2009_rtklib_revA.pdf</a>
<br>
before posting. <br>
There you may find more details about RTKLIB computational
load at 10Hz. <br>
<br>
Best regards, <br>
Michele <br>
<br>
<br>
On 02/05/2012 23:08, Danny Miller wrote: <br>
<blockquote type="cite">Well correct me if I'm wrong but this
seems to come down to how many flops it can do, the moving
of variables and such is probably a minority of the
processing. That's why I wanna focus on the flops
requirement. <br>
<br>
How much resources does RTKLib consume on Beaglebone?
Because BB being faster and capable of RTKLib still doesn't
establish the processing requirements. Is it running at 60%
core utilization or 5%? <br>
<br>
I did run RTKLib on my i7 Q 740 1.73GHz laptop and the
utilization was basically nil. I really couldn't determine
anything from that, the usage figure was too low to give a
meaningful number, not when the capabilities are at least
100x greater. I mean if the usage was 10% on that i7 I
could pretty well dismiss it working on a Cortex M4. IIRC
it was like a single-digit or fractional % though and the OS
can consume considerable resources managing the busses and
displaying the maps and interfaces so that doesn't mean
much. <br>
<br>
Raspberry PI would be nice, but I can't get ahold of one,
much less will it be readily available at this time for
widespread consumption if the application worked. I'm still
uncertain if widespread, long-term, low-price distribution
is gonna happen or just turn out to be vaporware. STM32F4,
anybody CAN order one or a thousand and get them for $15 or
better right now. Still got high hopes of course.
Raspberry PI also wasn't designed with a lot of low-level
hardware interfacing so it'd still require a daughterboard
like the STM32F4 to interface with a rover's motors and
sensors and all. <br>
<br>
Danny <br>
<br>
On 5/2/2012 3:40 PM, Michele Bavaro wrote: <br>
<blockquote type="cite">Hi Danny, <br>
<br>
I strongly doubt that a STM32F4 will be able to run
RTKLIB. <br>
It's true that it runs on a beaglebone, but Cortex-A8 has
around 2MIPS/MHz and runs at frequencies close to 1GHz, <br>
whereas a Cortex-M4 has 1.25MIPS/MHz and runs at
frequencies up to 150MHz: there is almost one order of
magnitude. <br>
In addition since the structure of rtkrcv is quite
strongly coupled with a Linux OS, <br>
there will be a lot of effort required to port it to a
lighter RTOS, let go to bare metal code. <br>
<br>
But I don't want to discourage you.. if you think it's
doable go for it :) <br>
<br>
Best regards, <br>
Michele <br>
<br>
On 02/05/2012 00:15, Danny Miller wrote: <br>
<blockquote type="cite">STM32F4 "demo board" uses an Arm
Cortex m4. 32 bit, 210 DMIPs and a single-precision
hardware FPU. I'm slightly unclear on the memory space
it has on this specific board but it should be 192KB
SRAM and 1MB flash. That's my porting plan. <br>
<br>
If it WORKS, it'll be a great system, these boards are
absurdly cheap. It is several more orders of magnitude
of capability than these 8bit PICs and such, but I don't
understand the scale of the flops requirement of
RTKLib. I know it's somewhere between "much more than
any 8-bit controller could ever do" and "won't even make
Intel i7 break into a sweat". And those are wildly
different magnitudes. I don't know exactly where RTKLib
10Hz would be between those. <br>
<br>
And it's be running RTKLib and just some minor
application (navigation and monitoring) code which will
not be processor-intensive, and it's not using Linux or
an RTOS. So there's not a significant overheat for
other tasks and the overhead's timing can be managed
predictably and accurately. Pretty much the core can
either do it or it can't. <br>
<br>
Danny <br>
<br>
On 5/1/2012 4:43 PM, julio menezes wrote: <br>
<blockquote type="cite">Hi Danny, <br>
<br>
<br>
<blockquote type="cite">I have a core with a hardware
FPU, but it's only capable of <br>
doing Single floats, not Double. It is going to
break <br>
things to implement the specified Double calcs with
Single <br>
precision? I would assume so, but it's worth
asking. <br>
<br>
</blockquote>
The RTKLIB author T.Takasu and A.Yasuda have ported
RTKLIB to a BeagleBoard which has an ARM Cortex-A8-
with 1 GHz and floating point, I do not know if double
or single precision. <br>
<br>
I plan to move in this direction also, may be using a
hardware less powerful but cheaper. <br>
Raspberry Pi <br>
<a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="http://www.raspberrypi.org/faqs">http://www.raspberrypi.org/faqs</a>
<br>
The SoC is a Broadcom BCM2835. <br>
This contains an ARM1176JZFS, with floating point,
running at 700Mhz, and a Videocore 4 GPU. <br>
<br>
I am waiting, anxiously, the RTKLIB 2.4.2 version
with RTCM-104 phase messages encoder to built a local
base station as where I live there are no near NTRIP
network ( less than 10km ). <br>
<br>
good luck, <br>
<br>
julio menezes <br>
<br>
<br>
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