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wide temperature range
Posted: Wed Jan 08, 2014 3:31 am
by kb1gtt
Are there any wide temperature range, multi core processors with a free compiler? My experience has been that the compiler is next to impossible to obtain for anything less than a large pile of $.
Re: RTOS options
Posted: Wed Jan 08, 2014 7:24 am
by blundar
kb1gtt: define "wide temperature range"
The best I can think of off the top of my head is going the be a Cortex A8 derivative, like Beaglebone Black. TI Sitara AM335x.
http://www.ti.com/product/am3358
They list an extended temp range model (-40 to 105C) in the datasheet. Whether it is unobtanium is a different story.
https://launchpad.net/gcc-arm-embedded
This GCC compiler supports Cortex-M0/M0+/M3/M4, Cortex-R4/R5/R7.
The TMS570 was intended for Automotive use by Continental. The TPU on it is fearsome. It's a R4, so theoretically supported by GCC. Dual core 180Mhz lock step. Pretty serious.
Re: RTOS options
Posted: Wed Jan 08, 2014 4:33 pm
by abecedarian
blundar wrote:kb1gtt: define "wide temperature range"
The best I can think of off the top of my head is going the be a Cortex A8 derivative, like Beaglebone Black. TI Sitara AM335x.
http://www.ti.com/product/am3358
They list an extended temp range model (-40 to 105C) in the datasheet. Whether it is unobtanium is a different story.
https://launchpad.net/gcc-arm-embedded
This GCC compiler supports Cortex-M0/M0+/M3/M4, Cortex-R4/R5/R7.
The TMS570 was intended for Automotive use by Continental. The TPU on it is fearsome. It's a R4, so theoretically supported by GCC. Dual core 180Mhz lock step. Pretty serious.
Many TMS570 are automotive qualified AEC-Q100, -40 to 125C, and there are > 200MHz variants available now.
I'll be playing with one soon.
Re: RTOS options
Posted: Thu Jan 09, 2014 10:53 am
by kb1gtt
Either Grade 0 (-40 to 150 degC) or Grade 1 (-40 to 125 degC) would be fine as far as I'm concerned. Also don't forget that there will be a temperature drop due to the thermal resistance to the heat sink. I generally look for an industrial ambient temperature range as it's what I have the most experience with, so I can draw off other experiences for the gut feel double check(s).
http://en.wikipedia.org/wiki/Operating_temperature for automotive I would generally consider the ambient to be −25 °C to 85 °C and with chips that need to be stay under 125C, that means the Rth has to allow for less than a 40C drop at what ever the max wattage is that will be dissipated by the PCB board. The more watts in the PCB means a larger heat sink to keep that temperature drop low enough. Err, any how, this is getting away from RTOS talk. If we keep talking thermal, perhaps we should create another thread.
Re: RTOS options
Posted: Sat Jan 11, 2014 9:43 am
by abecedarian
If we keep talking thermal, perhaps we should create another thread.
Please do. I don't see 85C, industrial and medical temps, anywhere near suitable for automotive and aerospace.
I know you realize those temp ratings are the basic 'standardized maximum permissible continuous operating' temperatures.
Maybe we need to start mentioning SIL and ASIL levels for components?
http://en.wikipedia.org/wiki/Safety_Integrity_Level
I really apologize for it if it seems I went off, but on the one hand it's "protect this and do that" and the next hand has "I don't care what temperature it's rated for as long as it's ...."
Things go hand in hand, and you know it. You can't pass 20A at 240V down 300 feet of 14 gauge wire and expect it to last long, since as you've already mentioned... insulation.
Re: RTOS options
Posted: Sat Jan 11, 2014 1:00 pm
by kb1gtt
abecedarian wrote:I really apologize for it if it seems I went off, but on the one hand it's "protect this and do that" and the next hand has "I don't care what temperature it's rated for as long as it's ...."
Comments found here
http://rusefi.com/forum/viewtopic.php?f=13&t=415
Re: wide temperature range
Posted: Sat Jan 11, 2014 9:55 pm
by abecedarian
Back on topic....
TI has TMS570 / R4 and Sitara (M3) boards that Code Composer Studio supports without limits, IF they have XDS100 emulation / debug.
Some of the libraries are restrictive, as in 'binary' only distribution, which could mess with open source tools.
CCS6 is supposed to incorporate Red Hat GCC as a compiler so that might open up some things for other processors.
Also, it's supposed to support Energia, which is an Arduino-like framework for TM4C and MSP430 MCU's.