**** BEGIN LOGGING AT Fri Sep 02 02:59:58 2016 Sep 02 19:12:01 Anyone there? Sep 02 19:14:17 ZeekHuge:there? Sep 02 19:14:31 somewhat .. Sep 02 19:15:01 ZeekHuge: can you tell me the fastest way to send data from pru to arm.. Sep 02 19:15:15 how fast do you need ? Sep 02 19:15:23 ZeekHuge: 200 hz Sep 02 19:15:35 well .. that pretty slow. Sep 02 19:15:44 I have got 5MHz Sep 02 19:15:54 ZeekHuge: how? using rpmesg? Sep 02 19:15:57 simply use rpmsg Sep 02 19:16:00 yes. Sep 02 19:16:06 for some reason.. Sep 02 19:16:08 ZeekHuge: it's very slow.. Sep 02 19:16:27 is it ? how can you say that ? Sep 02 19:16:54 I mean .. how are you measuring that ? Sep 02 19:16:55 ZeekHuge: I connected a hcsr04 ultrasonic sensor to beaglebone pru.. Sep 02 19:17:15 ZeekHuge: it sends data from pru to arm via /de/rpmesg31 channel.. Sep 02 19:17:37 so, one byte at a time or what ? Sep 02 19:17:39 ZeekHuge: it's like 3 or 4 readings printing per second Sep 02 19:18:02 ZeekHuge: yeah.. something like that.. Sep 02 19:18:11 how many bytes are there in one rpmsg message from PRU to ARM ? Sep 02 19:18:57 ZeekHuge: https://github.com/linux-creatures/beagle-addon/blob/master/main1.c Sep 02 19:20:41 will have to look into .. sorry wont be able to do that until tomorrow. Sep 02 19:21:06 Basically .. you can save a few readings and then send them all together at once. Sep 02 19:21:34 I was able to send data from the PRU at about 1MHZ Sep 02 19:21:46 and that was having 44bytes of payload Sep 02 19:22:11 ZeekHuge: can I directly print the data in a file? Sep 02 19:22:12 then ... changed the source a bit and was able to get sampling of 20MHz Sep 02 19:23:13 nope. Sep 02 19:23:26 you can copy to a file and that is obvious Sep 02 19:23:39 ZeekHuge: any faster option other than rpmsg Sep 02 19:23:41 ? Sep 02 19:24:00 that would involve much higher efforts. Sep 02 19:24:08 dont know if prudev can help Sep 02 19:24:46 ZeekHuge: what is the max capacity of payload in rpmesg? Sep 02 19:24:48 But quite sure you wont ned that. Sep 02 19:24:52 *need Sep 02 19:25:12 If you have some time, I will be happy to help. Sep 02 19:25:24 payload can be at max of 512 byte. Sep 02 19:25:29 actually less Sep 02 19:25:37 about 512 - 16 bytes Sep 02 19:26:21 but, if you store that amount of data on PRU, it will be stored probably on farther peripherals and that would make process slower Sep 02 19:27:35 ZeekHuge: so what do you think is the best optioN? Sep 02 19:28:37 save about 20bytes in a payload, and then send it all at once Sep 02 19:29:09 ZeekHuge: how about saving 128 bytes? Sep 02 19:30:16 that may cause delays at points. Now sure how fast you need this to work. Sep 02 19:30:31 but since its just a single pru, you can try that. Sep 02 19:30:47 but i would still suggest to use 20bytes approach first. Sep 02 19:31:05 also, make sure you are reading the /dev/rpmsg30 correctly Sep 02 19:31:32 actually I would ask this .. what command are you using to read /dev/rpmsg30 ? Sep 02 19:40:02 anyway .. just use xxd -c4 /dev/rpmsg30 ... this will give better results **** ENDING LOGGING AT Sat Sep 03 02:59:58 2016