I saw the STM32F429 Discovery kit, a little bit more cpu, 64 Mb ram, a TFTP display so could display the constellation, at about € 20.
Who is the first to port to that board? G On 08/21/2014 12:29 AM, glen english wrote: > Nice work David. > Maybe some one can let me know what the scope of topics of this forum > is. Hopefully, forum users will accept this brief off topic discussion. > I apologize in advance. > > Agreed with all on development cost. Depends on the market I guess. The > STM32 is actually right at the high end of complexities for the MCU > market. It is a complex device. But effective. > > From my aristocratic POV, 60mA at 3V is a real power hog for a battery > device, but- as you say David - IT MEETS THE OBJECTIVES , and that is > really what it is all about . Something either meets objectives, or it > doesn't . Anything else is just fluff. > > For a box that does not have to do much- simple sequential processing, > IE convert ADC, filter microphone samples- encode audio - add framing > bits - generate modulator samples, a simple interrupt driven job is fine. > > Now, throw in a bunch of asynchronous peripherals, peripherals that > must be talked to loaded with data, waited up for events to finish and > now you have a real problem with the sequential system, and the simple > kernel that provides waitable semaphores and timers and some basic co > operative multitasking is the answer, rather than a complex state > machine. And a basic kernel will only cost less than 100 cycles on a > context switch. In 2000 I wrote basic kernel for the AVR that did a > context switch in about 60 cycles. So, OS need not have much overhead, > and it is ideal when different people are writing for different > jobs/peripherals on the one chip. > > glen english > VK1XX > "yes - I do this for a living" > Altium- ModelSim, Matlab, Vivado, Rowley. > > > > On 21/08/2014 8:12 AM, David Rowe wrote: >> Hello Glen, >> >> Yes I agree re the STM32F4's DSP capability. It doesn't have proper >> single cycle MACs. However it's fast and cheap and has float so it does >> the job nicely. Curiously, no operating system ends up being kinda >> helpful on a CPU of this size. >> >> I measured 60mA at 3V on the STM32F4, that's the lowest power CPU I have >> ever played with! I estimated 24 hours operation on a pair of AA's. >> Plenty. >> >> I think if I was doing a multi-channel FreeDV device I'd use .... a PC. >> Just throw MIPs at the problem. Dead easy to develop on. I/O would be >> the only hassle. >> >> Cheers, >> >> David >> >> On 21/08/14 07:27, glen english wrote: >>> indeed Bruce. >>> >>> Consider I might be aiming at a portable device, or other low power, low >>> count silicon platform. (5$) >>> and bear in mind, I might want a heap processing power left over for >>> modulator/demod, error correction, some audio processing , noise >>> reduction etc. >>> >>> For those that know real DSPs, they'll recognize that the Cortex M4 >>> (stm32 4...) is NOT a real DSP. It has some handy instructions, they >>> call DSP, sure. But start throwing it alot of filtering tasks and you'll >>> run out of cycles. >>> >>> It is a very good general purpose processor though, excellent in fact. >>> I use it for all sorts of things when I don't care about power >>> consumption. The CODEC2 is not a simple DSP task, it is much more a >>> complex algorithm that doesnt get alot of help from a real DSP. The >>> STM32M4 is not a low power processor. >>> A real FP processor like the latest low power SHARCs ($10) for similar >>> money might do the job for less power, depending on the efficiency of >>> the coder- that's the thing to get the advantage of the real DSP, you >>> got to know what you are doing. The M4 will make fairly good throughput >>> out of junk coding. I use the Rowley Associates toolchain. >>> >>> >>> glen english >>> VK1XX >>> "yes - I do this for a living" >>> Altium- ModelSim, Matlab, Vivado, Rowley. >>> >>> On 21/08/2014 5:44 AM, Bruce Perens wrote: >>>> The reasoning is indeed that floating point is easier to develop and >>>> that our development time is more expensive than CPUs.We don't know >>>> the table sizes offhand. >>>> >>>> However, the assumption that both of the codec and modem would fit in >>>> really small and relatively low-power floating point chips was >>>> optimistic and as of this moment it's right on the edge of working in >>>> the STM32F405 that David has built into his SmartMic project. The >>>> STM32F405 is an ARM Cortex M4F at 168 MHz, 1 MB FLASH, 126K >>>> instruction/data RAM, and 64K data RAM. >>>> >>>> Over the past weeks David has torn through the code working on >>>> optimization, and at this moment the receive speed is "borderline". >>>> >>>> Thanks >>>> >>>> Bruce >>>> >>>> CPOn 08/20/2014 11:42 AM, Steve wrote: >>>>> I think the reasoning is, that floating point and memory are so cheap >>>>> now, that trying to fit a design into a restricted space would just >>>>> lengthen the time to profit. >>>>> >>>>> Why design to a fixed point $30 DSP when you can buy a $5 CPU with >>>>> hardware FP. >>>>> >>>>> 73,Steve >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> Slashdot TV. >>>>> Video for Nerds. Stuff that matters. >>>>> http://tv.slashdot.org/ >>>>> >>>>> >>>>> _______________________________________________ >>>>> Freetel-codec2 mailing list >>>>> [email protected] >>>>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >>>> >>>> ------------------------------------------------------------------------------ >>>> Slashdot TV. >>>> Video for Nerds. Stuff that matters. >>>> http://tv.slashdot.org/ >>>> >>>> >>>> _______________________________________________ >>>> Freetel-codec2 mailing list >>>> [email protected] >>>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >>> -- >>> - >>> Glen English >>> RF Communications and Electronics Engineer >>> >>> CORTEX RF >>> & >>> Pacific Media Technologies Pty Ltd >>> >>> ABN 40 075 532 008 >>> >>> PO Box 5231 Lyneham ACT 2602, Australia. >>> au mobile : +61 (0)418 975077 >>> >>> >>> >>> ------------------------------------------------------------------------------ >>> Slashdot TV. >>> Video for Nerds. Stuff that matters. >>> http://tv.slashdot.org/ >>> >>> >>> >>> _______________________________________________ >>> Freetel-codec2 mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >>> >> ------------------------------------------------------------------------------ >> Slashdot TV. >> Video for Nerds. Stuff that matters. >> http://tv.slashdot.org/ >> _______________________________________________ >> Freetel-codec2 mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
