#qi-hardware IRC log for Saturday, 2010-12-11

kyakxiangfu: http://qt-apps.org/content/show.php/kinyin?content=9592605:33
kyakxiangfu: might be interesting for you :)05:34
virickristianpaul: trabajas en Loongson2f ahora? :)06:16
viricxiangfu: did you commit that 'nerase' change?06:17
viricxiangfu: (I'm lazy to erase the flash... Do you know how should I backup my ubifs for a later nprog ?06:17
viricxiangfu: ni hao ma?06:21
xiangfuviric: mount the root to another folder. then use mkfs.ubifs to create an ubi file base on this folder. :)06:28
virichmmm is it 'the way'? :)06:28
xiangfuviric: that is come out first in my mind. :)06:29
viricah ok06:29
xiangfuviric: I am not commit that change.06:30
viricxiangfu: why don't you commit it?06:31
viricxiangfu: don't you think it is better than now?06:31
xiangfuviric: I am not well test that change.06:31
xiangfuviric: recently I always working on the openwrt image.06:31
xiangfuviric: and u-boot, a little slow on nerase. :(06:32
kristianpaulviric: hace un tiempo tengo uno07:09
kristianpaulviric: y ciertas cosas no ejecutan bien, por falta del SIMD :S07:09
kristianpaulviric: tambien queria comparar el simd del loonsoon con el del xbusrt a ver que puedo esperar de ambos07:12
virickristianpaul: yo tengo un par de minipc07:13
virickristianpaul: qué no "ejecuta bien"?07:14
kristianpaulviric: gps-sdr.com07:14
viricno carga07:16
kristianpaulno :(07:17
kristianpaulme hace falta, no se que paso no se a quien contactar para preguntas07:17
kristianpaulalmenos tengo el codigo07:17
kristianpaulhmm espera07:17
kristianpaulviric: http://www.ctae.org/sdr/ (mirror del codigo)07:18
virichey the USRP gnu radio is super expensive :)07:21
kristianpaulyes , but i plan get one any time next year i hope07:22
kristianpaulis relly usefull for debugging07:22
viricit looks very ogod07:23
virica radio laboratory should have one07:23
kristianpaulviric: less espensive that buying separate radio stuff07:24
viricI agre07:24
kristianpaulalso you add it a ITX board and you're done07:24
kristianpauli saw openBTS shop and they sell it with on, is good idea07:24
viriccan it do CDMA?07:24
kristianpauli dont know07:25
virickristianpaul: how you test the speed on the minipc for the gps code'07:26
kristianpaulcorrelation time, but first i need pass the simd-like self test  :)07:27
virickristianpaul: cómo lo pruebas?07:30
viriccan't you test it without simd?07:31
kristianpaulhehe , no i think , simd is heart for acquisition step07:32
viricdoes the loongson2f have simd instructions for floating point?07:36
viricor your calculations don't involve floating point?07:36
kristianpauli dont know yet, i need read manual first07:37
kristianpaulfloat point dont know either, is just FFT from data-like -1,0,107:37
viricfor what I read...07:40
viricit only has integer SIMD instructions07:40
viricso, they can work as fixed point.07:40
kristianpauldamn mocp dint fit on nanonote screen :/08:25
wpwrak_kristianpaul: (simd) you mean the correlation ?08:27
kristianpaulMMX like instructions08:28
wpwrak_kristianpaul: yes, but for what kind of operation ?08:28
kristianpaulwpwrak_: fft08:29
wpwrak_ah yes, fft should be happier with that08:29
viricare you using fftw3?08:45
kristianpauli will for first test, but i want to try re-use gps-sdr code later08:47
qi-bot[commit] Cristian Paul Peñaranda Rojas: Sync signal to mcu is taken from SiGE as result removed non needed code and fixed identation http://qi-hw.com/p/ben-gps-sdr/f7203fa09:07
qi-bot[commit] Cristian Paul Peñaranda Rojas: Updated simulation, reset trigger removed http://qi-hw.com/p/ben-gps-sdr/f0ae34209:07
qi-bot[commit] Cristian Paul Peñaranda Rojas: Pin asigment is completed http://qi-hw.com/p/ben-gps-sdr/c37929709:07
qi-bot[commit] Cristian Paul Peñaranda Rojas: Added README with basic description and spected behavior http://qi-hw.com/p/ben-gps-sdr/31ad2b409:12
qi-bot[commit] Cristian Paul Peñaranda Rojas: Updated makefile to be more friendly and removed non required features http://qi-hw.com/p/ben-gps-sdr/4e57bf809:21
kristianpaulsomething really weird happen after load bistream to fpga, screen just got crazy :/ and i lost ssh conection15:03
lekernelon sie?15:04
kristianpaulhmm is my bitstream15:11
kristianpaulwhat's wrong with port A :/15:12
kristianpaulIn theory i just send a 4bits data plus a clock signal at 2.048Mhz15:16
Madridmanplease anybody could recommend the best book to learn about gpu's? basics16:52
MadridmanI would like to learn the typical GPU's architectures, theorical things17:06
Madridmannot interested in programming GL and such17:07
Madridmaneverybody's sleeping?17:07
viricare you more interested in the power supply and clock of the GPU?17:08
lekernelMadridman: if you're interested in how GPUs are made, have a look at my thesis (on milkymist), and specifically the chapter on the texture mapping unit (tmu)17:11
lekernelthe tmu implements several fundamental features of GPUs17:11
lekernelbut if you have no prior experience with opengl, I'd recommend playing around a bit with it for starters17:11
lekernelit will really help you understand what is going on17:11
Madridmanlekernel I would like to check your thesis, where is milymist?17:12
Madridmannot interested in opengl, just electronic architecture theorics17:12
Madridmani do not pretend to program17:12
lekernelwell, opengl understanding will really come handy17:12
lekerneland opengl is already pretty low-level itself17:13
Madridmansure but before it could be good to know how the memory etc. are placed17:13
Madridmanall the buses and rest of components17:14
viriclekernel: is the milkymist source available?17:14
lekernelyes, of course17:14
viric(to me, I mean, for example :)17:14
MadridmanI know plastation and xbox have nothing to do one each other17:14
viriclekernel: is it in vhdl?17:14
lekernelno, verilog17:14
viricouch. Bad luck I had. :)17:14
lekernelverilog is little more than a less verbose vhdl, so if you already know VHDL well enough you'll have little trouble with verilog17:15
Madridmanlekernel sorry, I accessed the web page http://milkymist.org/ but I don't know where is the theorical part of your thesis17:15
viricI never tried verilog.17:15
Madridmanthere is a part about architecture?17:15
lekernelis it so hard to find that link? http://www.milkymist.org/thesis/thesis.pdf17:16
viricI'll steal it too17:17
Madridmanlekernel that fpga can compete with a commercial architecture?17:18
MadridmanI mean is slower?17:18
lekernelhaving seen a demo of ARM Mali on a FPGA, I think it does :)17:18
lekernelat least performance-wise17:18
lekernelbut it lacks some features (that I didn't need for my application) to make a complete GPU that supports all OpenGL application17:19
viriclekernel: do you use any floating point there?17:19
Madridmana fpga can be as fast as a commercial video card as ati or nvidia?17:20
lekernelthe texturing unit is fixed point, but the pfpu (roughly, a vertex shader) uses 32-bit ieee 75417:20
lekernelfloating point17:20
lekernelMadridman: generally no17:20
lekernelat least for GPU operations17:21
Madridmanso fpga's are not as useful as they say17:21
Madridmanthey has limitations17:21
lekerneleverything has limitations17:22
lekernelthe fpga is however a lot more flexible than a gpu17:22
Madridmanok, do you know a book or web or resource which speaks about fpga's so I could know better them?17:22
viriclekernel: aren't Floating Point operations taking lots of logic in the fpga?17:22
Madridmanjust general theory17:23
lekernelso if your particular application doesn't map nicely to, say, CUDA code, the FPGA can still deliver there17:23
lekernelviric: no, I'm not using the Opencores FPU ;)17:23
viriclekernel: where did you get the FPU operations from then?17:24
lekernelI wrote some code...17:25
Madridmanlekernel do you know a book or web or resource which speaks about fpga's so I could learn and know better them?17:25
lekernelit's not 100% IEEE 754 compliant btw17:25
lekernelthe number format and a lot of things are the same17:26
viricMadridman: get a manual from an FPGA seller17:26
lekernelbut I don't totally respect details of the standard such as the way of rounding numbers17:26
viricMadridman: get the manual for the spartan3 fpga for example.17:26
lekernelor how to deal with numbers like NaN or infinites17:26
Madridmanviric but I want to know the general common basics, not a concrete seller17:26
lekernelagain - I don't need those for graphics processing17:26
MadridmanEg. which kind of transistors or biestables are used generically, etc17:27
viricMadridman: that thing you call "generic fpga" does not exist. There are only concrete FPGAs :)17:27
Madridmanok, imagine I'm new (what is absolutelly true), I never heard about a thing called FPGA. You can't give a manual of a concrete implementation because I don't know even what technology we are speaking about17:28
viricMadridman: look for the "Spartan 3 User Guide"17:28
Madridmanthat looks as a board to do circuits17:30
lekernelMadridman: http://lekernel.net/presentations/FPGA_Workshops/17:30
lekernelhttp://lekernel.net/presentations/FPGA_Workshops/091108_tmplab/scenes_draft.pdf will generally explain you how they work internally, but you may want to have some practical experience before17:31
viricMadridman: I call FPGA a chip that can be programmed *by software* to mimic a logic circuit. Software allows you to rearrange whatever is there inside to get as if you had made a circuit concerning whatever FPGA pins you want.17:32
Madridmanok, but later what you get is a physical circuit isn't it?17:33
Madridmani mean, logical gates interconnected17:33
Madridmanok, that pdf's seems to have theorical information too, that's what I need for starters17:35
viricThe circuits there come at some limitations, of maximum clock frequency, maximum number of clock signals, maximum number of flip flops...17:35
viricthe more you pay, higher the limits17:35
MadridmanI understand17:36
Madridmanthe scenes draft looks nice17:37
viricthere are hardware description languages, and most FPGA sellers offer 'compilers' for those common languages to whatever their FPGA needs.17:37
Madridmanyes, as vhdl which I hates17:37
viricSo you can describe your circuit in a common way, and expect it to work among different FPGA vendors.17:37
viricMadridman: there is also verilog17:37
Madridmanfor sure is much better17:38
viricno idea.17:38
viricand how you have such an opinion about that? Some minutes ago you did not know anything about FPGA17:38
Madridmanthat's because I need theorical resources, to avoid bugging you17:39
Madridmanis reallistic to pretend have a fpga's hardware which competes against commercial circuits (performance, fabrication costs)?17:39
Madridmanso it'sr just experimental things oriented?17:40
lekernelby "commercial circuit", you mean full customs ICs?17:40
Madridmanwell, a microprocessor yes17:40
viricFPGAs can compete only in the sense that they can be 'reprogrammed'17:40
lekernelin a typical design 90% of the FPGA transistors are wasted17:40
viriclekernel: hey, talk for your designs17:41
Madridmanmy university research for multiexecution architectures specific for some tasks, so there are just experiments17:41
lekernelbut if you compare that to the NRE of spinning an ASIC, sometimes it makes economic sense to keep an FPGA in a product where the FPGA design remains static17:41
viricFPGA over ASICs may have advantages on a) reprogrammability and b) cheaper for small productions17:42
Madridmanthank you so much, you both provided me a lot of information17:59
qi-bot[commit] David Kühling: First shot at an Emacs package.  Experimental! http://qi-hw.com/p/openwrt-packages/bea9c0118:35
virickristianpaul: using that will require more than thumbs18:48
kristianpaulwpwrak: do you have a signal generator at home?19:53
wpwraka Picotest G5100A20:02
kristianpaulI'm testing fpga bistream for the serial to parallel stuff on SIE20:03
kristianpaulas soon i get loaded the bitstream the LCM got odd interfereance and i lost ssh link20:03
kristianpauli'm not sure if is mestastabillity or something ii'm forgoting to set in port A20:04
wpwrakhmm. so the FPGA is crashing the CPU ?20:04
kristianpauli need dig more, i'll do try and error as i lack scopemeter and signal generators at home20:05
wpwrakmaybe you're mis-initializing some of the pins ?20:05
kristianpauli think20:05
kristianpaulchecking that righ now20:06
wpwrakdo you have any other program for the fpga that works ?20:06
kristianpauland it worked as usual20:06
wpwrakodd then20:07
wpwrakwell, you can try translating the one that works step by step to the one that doesn't :)20:08
kristianpaulwell i could i just wanted do do it before this ;=20:08
kristianpaulis just too elaborated for what i wanted to do20:08
wpwrakwhat is too elaborated ? the debugging process ?20:09
wpwrakor the "good" one ?20:09
kristianpaulwell is NOT so much, it just was intended to drive FPGA as a memory20:10
kristianpaulso you have a buffer to write and read, thats the general idea20:11
wpwrakah. a bit complex indeed. probably more complex than the serial to parallel converter20:11
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