I just went through this pain and the people in this group were awesome help.
I needed to read three analog inputs and it was a bear but once I got it, it has been going well. You don't mention the OS of your development platform or I may have missed it. I'm on a Windows 10 box and using a BBB Wireless. TI's entire learning system for this expects a Linux development platform so it's not as useful as it could be if you are on Windows. I didn't want to go to the trouble of even bringing up a virtual Linux on my Windows box for this. I did install Code Composer Studio (CCS) from TI, but gave up on it. There's no easy way to transfer your compiled firmware to the BBB from within it according to TI. So I just do everything on the Beagle and it meets my needs. I use the cloud9 IDE that ships with the BeagleBones for coding both the ARM and PRU code. This environment compiles the ARM-side code and executes it just like any normal host (aka Linux, aka ARM) program just fine. However, to compile the PRU code and load it I go over to a PUTTY session and use the make files from Mark Yoders' PRU Cookbook (https://markayoder.github.io/PRUCookbook/) . My process is clunky but my programs aren't huge or extremely complex (yet) and this works for me. I don't have and don't want to invest in a debug probe so debugging the PRU code can be a pain and slow. The only option really is to use RPMsg almost like printf to send messages back at key points in the PRU code to let me know where it is executing and what's happening. (Purists and more advanced developers are barfing and laughing at me right now I am sure.) I strongly encourage you to get the Technical Reference Manual for the TI ARM335x and specifically spend time with the Touchscreen Controller chapter. If you need precise timing, you'll want to spend time in the Industrial Ethernet Peripheral chapter too. These are powerful tools once you understand them. Also, get the PRU Optimizing C/C++ Compiler manual from TI and go through it. One thing that really tripped me up was their implementation of the __far keyword. GCC doesn't recognize that and I didn't understand what was going on at first. As Mark commented, some people encourage using remoteproc, some encourage using libpruio and some still use the uio. TI supports remoteproc and I expect them to be around so I went with remoteproc. It may have its drawbacks but it is working just fine for me. I can't comment on the other two as I have not tried them. Also, I've found the TI E2E forum's moderators to be patient with me as a neophyte. But the Google group's members do have wider experience. FYI - watch out for how TI puts some register settings that cross nibble or byte boundaries. It can really bite you! Take a look at the STEPCONFIGn registers implementation of averaging to see what I mean. I hope this helps! On Saturday, May 1, 2021 at 12:46:03 PM UTC-4 lazarman wrote: > <<<My first intention is to post in TI E2E support forums > <https://e2e.ti.com/>, but it requires a company email to do so. > > Hello Cheng > > I want to Help you but it appears my message is lost in translation > > What it sounds like to me is TI pays these engineers $$ to answer > questions and does not want to waste time and $$$ with users that dont > follow their well written instructions *which say use SDK Yocto Linux on > the ARM for this example.* > > For me I start with a working example with instructions and documentation > then modifyit > > If I undertsand correctly you have *never* had an example working > > If you like breaking examples and working on projects that ONLY works from > a unix script and hides all the details then this is the correct group to > to ask questions (-: > > I suggest you try the example *you found* following the intructions > exactly. if you cant or wont do that switch to DEbian/Cookbook > > But if you do the latter I suggest don't change things follow the > instructions > > What is interesting is a Linux C application program should work correctly > if it was coded generic especially when both Linux variants are for the > same chip. Trying to figure out what is different between Linux variants to > me is not productive its not my focus for you maybe it is. > > Perhaps the Linux in the SDK was configured differently which implies it > handle PRU slightly different Im not surprised by this. > > Perhaps you can find what's different that may be a valid approach that > works for you and maybe someone can help. I think Dennis gave you a good > clue. > > I will watch the thread hopefully I can be of help should you choose to > follow the path E2E and the SDK layed out for you > > Cheers > > On Friday, April 30, 2021, 07:52:09 PM CDT, Cheng Chen <chen...@gmail.com> > wrote: > > > Hey Mark, > > Thanks for spending time for replying. I really appreciate it. > I totally agree with you that one should spend time investigating first. I > apologize if they are dumb questions, but I have stuck there for two weeks. > I am more a circuit guy and just started picking up Beaglebone as a hobby > and potential career expansion. > > My first intention is to post in TI E2E support forums > <https://e2e.ti.com/>, but it requires a company email to do so. If this > particular .org is not a good place for rookie questions, would you please > advise some place for suitable for discussion? > > Regarding to the documents, are you referring to processor SDK Linux > Software Developer's guide? If that is the one, I did follow its > instructions, but maybe I missed something. I will go over it again. If > that's not the one, which document are you referring to? I also went > through PRUcookbook and Exploring BeagleBone by Derek Molly. Not a lot are > mentioned regarding this topic. > > The code is built-in in the Beaglebone Black, this is one of the reasons I > am confused why it cannot be compiled. One can also download freely from TI > github ( > https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package/ > ). > > Again thanks for the advice and suggestion. I am very glad that there is > such a nice place that I can call for help and I hope after some practice I > am also able to contribute here. > > Regards, > Cheng > > 在2021年4月30日星期五 UTC-4 下午5:09:01<lazarman> 写道： > > Hello > > I know the code. It's all explained in the SDK documention. I also like > these examples. > Your asking questions about an SDK that's supported by Texas Instruments. > You do understand this .org group you posted in may contain TI employees > but is NOT TI support it's Beagle board Debian. > > I think if you read the documents you will understand the answers > > I'm sure you could compile this with some work the sdk instructions talk > about This. > > Hypothetical question ❓ > If the instructions told you a virtual box build was not supported and not > recommended would you use one anyway and then ask the person who told you > not too do this why it doesn't work. > > I'm struggling to be nice in this reply. > > I remember asking questions as a young engineer that clearly showed I > made zero effort to research anything. > > Then one day I got some really critical replies about my skills. > > Do some reading then if stuck ask questions > > Or better yet follow what the sdk instructions suggest. > > If you found this code on internet and don't have a TI account or are not > eligible for ITAR restrictions to download the sdk you have a big problem. > > I see you have a Gmail account > > > > > > > Sent from Yahoo Mail on Android > <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature> > > On Fri, Apr 30, 2021 at 3:09 PM, Cheng Chen > <chen...@gmail.com> wrote: > > Hi all, > > I am practicing PRU skills through some TI examples. I am playing with > PRU_ADC_onChip > > <https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package/tree/examples/am335x/PRU_ADC_onChip?h=master>example > > and ran into a few questions. I wonder if you can help me with. > > The nice thing about this example is it has a README.txt with all the > procedures. The idea is to use rpmsg to communicate between arm and pru > module and read out ADC value. > I am using a Beaglebone Black wireless. > Here is the basic procedures. > > FILE STRUCTURE > PRU_ADC > | > |--pru_adc_firmware.c firmware loaded into PRU0 > | > |--pru_adc_userspace > |--pru_adc_userspace.c userspace code that interacts with PRU0 > > BUILD FIRMWARE & USERSPACE CODE > $ cd <PATH_TO_PRU_SW_SUPPORT_PACKAGE>/examples/am335x/PRU_ADC_onChip/ > $ make clean > $ make > $ cd pru_adc_userspace/ > $ make clean > $ make > > My BBB wireless can compile pru code successfully because I installed > PRU_CGT compiler. But it is unable to compile ARM code. I think that is > because ARM_CCT cross-compiler toochain environment is missing, in another > word, I need to install processor-sdk-am335x > > My first questions is can I install processor-sdk-am335x into Debian > system I currently have (Linux beaglebone 4.19.94-ti-r62 ) ? I am a little > confused about the relationship between this SDK and Debian system. Why is > the tutorial asking me to compile pru_adc_userspace.c in the Beaglebone. > I thought it is supposed to be executed in a cross-compilation environment. > > I ended up installing processor-sdk-am335x on my linux desktop and > compiled successfully. Then I copied the generated file back to BBB > wireless. But when I tried to run the program, it shows the following > error. > > Reading voltage at ADC Channel: 5 > /dev/rpmsg_pru30 could not be opened. > Trying to initialize PRU using sysfs interface. > ERROR: Could not open /dev/rpmsg_pru30 > > Attached is the excerpt where the problem happened. Could anyone help me > with some hints of what is going on here? Much appreciated. > > > struct shared_struct message; > > /* use character device /dev/rpmsg_pru30 */ > char outputFilename[] = "/dev/rpmsg_pru30"; > > /* test that /dev/rpmsg_pru30 exists */ > FILE *ofp; > uint16_t returnedVoltage; > ofp = fopen(outputFilename, "r"); > > if (ofp == NULL) { > > printf("/dev/rpmsg_pru30 could not be opened. \n"); > printf("Trying to initialize PRU using sysfs interface.\n"); > > FILE *sysfs_node; > char firmware[] = "/sys/class/remoteproc/remoteproc1/firmware"; > char firmwareName[] = "PRU_ADC_onChip.out"; > sysfs_node = fopen(firmware, "r+"); > if (sysfs_node == NULL) { > printf("cannot open firmware sysfs_node"); > return EXIT_FAILURE; > } > fwrite(&firmwareName, sizeof(uint8_t), sizeof(firmwareName), > sysfs_node); > fclose(sysfs_node); > > char pruState[] = "/sys/class/remoteproc/remoteproc1/state"; > char start[] = "start"; > sysfs_node = fopen(pruState, "r+"); > if (sysfs_node == NULL) { > printf("cannot open state sysfs_node"); > return EXIT_FAILURE; > } > fwrite(&start, sizeof(uint8_t), sizeof(start), sysfs_node); > fclose(sysfs_node); > > /* give RPMSG time to initialize */ > sleep(3); > > ofp = fopen(outputFilename, "r"); > > if (ofp == NULL) { > printf("ERROR: Could not open /dev/rpmsg_pru30\n"); > exit(EXIT_FAILURE); > } > } > > > > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/1d43aa7b-0e94-4431-9e31-13545213940bn%40googlegroups.com > > <https://groups.google.com/d/msgid/beagleboard/1d43aa7b-0e94-4431-9e31-13545213940bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard...@googlegroups.com. > To view this discussion on the web visit > > https://groups.google.com/d/msgid/beagleboard/39813de1-fa27-41d7-9422-7ef375ae36b4n%40googlegroups.com > > <https://groups.google.com/d/msgid/beagleboard/39813de1-fa27-41d7-9422-7ef375ae36b4n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/88525d79-e91c-470f-9800-ab96cb985398n%40googlegroups.com.
